Jay and all followers of this thread,
My apologies for being late to the game here. I literally have not had the bandwidth, literally or figuratively, to follow this. I have not read all posts, so I apologize if some of this is repetitive or too late to the game.
Nonetheless, I thought I would put these "overlanding design & build & utilize lessons learned" up here so others who read this build thread could learn from them, rather than continue to PM them only to Jay & Alice.
* I don't know if you've addressed it or not, but one thing almost every German rig has and we wish, every day, that we had, is dedicated, weatherproof, exterior storage for shoes and boots, and a corresponding space inside the camper for the same thing. This will be even more of an issue with your shotgun-riding, Bob The Builder watching son and good-eater daughter. We raised four of them, so we have an inkling of what lies ahead in that regard… 8^)
* Another peek ahead into your future, Jay, lies in the transition from designer/builder to overlander. When you leave you will be carrying a tremendous amount of inertia around the design & build phase of this experience. You will probably tend to view your day-to-day existence through the designer/builder/tester filter. Traveling & testing in North America will probably not dispel much of it. You will undoubtedly be chasing down niggling bugs and sorting out systems for quite a while with your rig. My unsolicited advice is to invest conscious, dedicated time and energy into making the mental transition into the overlander mindset, lest your first year or two be not much more than an extended field test of your design theories and systems maintenance abilities. You could wake up at the end of your time and realize that you spent most of your overlanding experience operating in a mental model of displaced designer/builder rather than participatory overlander. KWIM?
* 24v was absolutely the right decision for the reasons you cited and more.
* Along the same lines, even if you've started wiring or procured your appliances, build this vehicle for 220VAC/50-60Hz. Unless you are in Japan or between the arctic circle and Ecuador, you will be living in a 220V world. Need a new tea kettle or toaster? Prepare for the usual 2-3 week customs dance unless you're on 220.
220v appliances are available through marine suppliers. I'm assuming you are using a marine AC/DC distribution panel and they are all 220V compatible. If you've procured 110v appliances then return them or sell them and install 220. You will, inevitably, need to interface to the outside electrical grid for a variety of reasons in a variety of scenarios. While a 220V/50-60Hz battery charger will keep your house bank charged, the ability to easily interchange and interconnect your internal AC electrical world with the outside world will make your life very much easier. At this point you probably are dreaming of multiple years completely off the grid, camped in remote places, far away from civilization. In reality, you will spend a lot of time in and around civilization, especially if you find a community you very much enjoy and want to stay for a few weeks or months to really get to understand the culture and people. Those people will be on 220VAC. The ability to plug in will make your life a lot easier. You don't want to annoy those new friends running your genset. And that's just the beginning of the reasons why...
* There is only one grounded circuit that I know of in South America. It's grounded because I built it (Otavalo, Ecuador). This is probably true of most of the rest of the developing world. Consequently, all those times you will want to plug in to avoid offending the neighbors with your genset, you'll want to be grounded. Go to Lowes or Home Depot and buy a one meter copper ground rod and a corresponding cable clamp. Get two or three meters of heavy gauge stranded cable. Create a grounding lug on your chassis. You'll already be carrying a 2lb. hammer to drive the rod. Test this setup and connection while you're in North America. It's quick, easy and could save the life of one or more of your family.
* If you stay with 110VAC/60HZ systems, note that a stepdown transformer (220-->110) only changes the voltage, not the frequency. Read the data plates on EVERYTHING you may plug into your 110V system while you are running on externally provided AC. Make sure each device is capable of operating on 50Hz (frequency) AC power. Charles Marine makes excellent 220/110 isolation transformers like this one we left at the campground in Otavalo.
* Redundancy is the most important thing you can design into your rig. By that I mean you must have multiple ways to do every essential thing. Be able to cook food by multiple means (petroleum products or electricity), be able to heat your hot water tank by multiple means, be able to heat your camper by multiple means, be able to make coffee/tea by multiple means, be able to take on fresh water by multiple means, etc.
* A vehicle of your weight is self-limited in the developing world to market town roads. Non-market town roads are built to the width and weight of a Toyota HiLux (Tacoma). We know overlanders with rigs your size and weight who have broken through bridges because their track was too wide for the support beams of the bridge. We know overlanders with rigs your size and weight who broke through bridges, salt crusts, etc., due to their weight. At your weight, you could run six axles with flotation tires and you will still get stuck on a deeply mudded track. If you are going to be this heavy and big, then realize that this will not be a vehicle in which you will be doing any 4x4 travel in the U.S. sense of that sport/mode of travel. The only way you will see that type of two-track and live to tell about it is on the back of a burro or in the back seat of a local's HiLux.
* Due to the factors in the preceding paragraph, make sure you include Euro pindles (receivers) and a Euro truck tow bar on your rig. There will always be another big truck along that can and will pull you out. The times when you will need to be self-extracting on a market town road are very few. By the time you get the triple pull rigged, there will be a two kilometer line of trucks, buses and cars honking in both directions.
* In a rig your size and weight, comfort and convenience for your lifestyle is much more pragmatically a priority than absolute vehicle capability. You will use this rig to travel from interesting place to interesting place. It is too big and heavy to 'go where no expedition camper has gone before,' and besides, full-time, living, overlanding is not about risking your only home on a narrow mountain goat trail, it's about getting to the next interesting place alive, in one piece, all systems Go, and, as Diplostrat says, with no bullet holes.
* You will become very attached to your home, your own bathroom, your own pillow, your own reading lamp, your own laptop work space, etc. Any thoughts you have now of stopping in a nice hotel/resort/etc., once a month or even every few months, will likely slip away pretty quickly.
* The world is a very safe place. All the thought and work you put into security systems will largely go unused. Carl Hunter put one of those external circular locks on his cab doors. He told me that in circling the world and a subsequent year in South America he used them once. Petty theft is the biggest concern. Don't leave anything exposed that is not locked to the truck. Ensure all compartments lock. Don't leave any fill points (diesel, LP, water, etc.) exposed. Make sure they are all behind locked compartment or access panel doors. Get a custom cover made for the camper portion of your rig. When you leave the rig for a few weeks or ship it, put the cover on it. Make sure you can operate the truck with the cover in place. Buy and religiously use sunscreens for the windshield and the side windows. Make sure all cab electronics (GPS, iPod, etc.) are behind closed panels/compartments when not in use. Out of sight, out of mind is the rule out here.
* You will drive at night. Guaranteed. Despite your best intentions and your cross-your-heart-and-hope-to-die promises to your mother, you will drive at night. Consequently, you need to be prepared. You need excellent fog lights and at least one set of HID driving lights. We also have pencil beams. We have used them all. Lots. Your goal should be the same as I gave our fabricator: "I want to be able to vaporize any bug that flies in front of the truck." We have never accurately measured our reach, but our lights are made for off-road racing in Baja. We can illuminate a mountainside several kilometers away as we swing around one-lane mountain curves at night. Even in the rain. You will be there too. Be prepared.
* Rub rails work. We learned on the motorcycle that buses, trucks, cabs, etc. consider driving a contact sport. In some parts of the world, people drive by the braille method: if they can't feel you they don't know you are there. You can't get upset about it, you have to consider it the 3rd world version of NASCAR, where "rubbin' is racin'." We installed longitudinal rub rails at about 1.5 and 2.5 meters altitude down the sides of our payload. They have seen extensive use and have saved our camper numerous times. We would have been back home a long time ago without them.
* Brush guards and lanyards work. Have a high strength aluminum external cage built for your cab. Make sure it protects the circumference of your windshield and the grill/lights. Run stainless steel cable lanyards with integrated bungee cord shock sections from the top corners of the brush guard to the corresponding leading top corners of your camper box. The lanyards are to guide brush and trees around your camper. They work.
* Nerf bars work. Build high strength aluminum nerf bars for the front and rear roof of your camper box. Ensure they are a little bit higher than anything on your camper box roof. You will need these. They work.
* On a vehicle your size and weight the standard dimensions and angles that get beat to death on Expo and other forums don't matter much. Approach is a non-issue. We have a tiny breakover angle and have never contacted our skid plate. Departure angle is an issue at ferries. We have contacted our departure rub rails & caster wheels once. You will not be descending or ascending steep riverbanks with this rig. It is unlikely you will be doing the wild river crossings on the road of bones. On the market town roads you will be traveling on, you will be doing river crossings with delivery trucks and chicken buses. They will have very modest angles.
* Entertainment is important. There will be times when you will be, for various reasons, holed up inside your camper for days and possibly weeks at at time. A collection of DVDs, a flat screen and wireless surround sound headphones can be a real family/marriage saver in those situations.
* Silence is golden. Sound insulate your cab. Maintain a very quiet exhaust on the truck and genset. Make sure every child and adult is equipped with headphones for anything that generates sound.
* Your own space is critical. The most essential factor for a happy sailing crew is ensuring that every crew member has a space, even if it is the size of a shoebox, that is entirely, totally, and without exception, their own private space.
* "No plan survives first contact with the enemy." - Helmuth von Moltke the Elder (1800-1891). Many, if not most, of the things you cram onto the truck because you are convinced you can't live without them will go unused. Almost all of the assumptions about the way things are in places you haven't been before will be wrong. Places you plan to visit will go unvisited. What you think you will do tomorrow will go undone. Assumptions you make about anything and everything, from the smallest thing to the biggest thing, will not be realized. Not a single plan you are making now will even faintly resemble what you end up living. Smile, it's all part of the adventure. Remain flexible and adaptable.
* Excellent cooking utensils are essential. Bring top quality commercial pans. Bring excellent knives. If you were going to eat in restaurants and stay in hotels you would have built a hotel-to-hotel vehicle. You will be shopping in the local markets and cooking what is fresh. Make the cooking a pleasant, top quality experience.
* Contrary to a primary tenant of belief of a certain European country which I will not name, life does NOT have to be hard. Life can be, and IMHO should be, a pleasant and rewarding experience. You do not have to suffer deprivations nor make daily sacrifices to realize huge life-rewards and wisdom from this overlanding experience. Bring stemware. Buy and enjoy good wine.
* Do not bring staples, but bring special treats. You can buy basic food--excellent, fresh, basic food anywhere. You cannot, however, always get your favorite treat or spice sold only at Trader Joe's. Stock up on the things that make your life and your cuisine enjoyable. You can buy everything else out here.
* You can repair anything made of metal, wood, fabric or leather in the developing world. You will find no junkyards out here because they are either still on the road or have been stripped right down to the beep of the horn. This world specializes in keeping things going. If you have an electronics failure, you will need to be carrying spare parts.
* Dealer support is delusional. You will find, as many MB owners have, that just because there's a dealer in lots of places, it doesn't mean they have the part you need for your truck, even if it's a round nose MB, probably the most popular heavy vehicle on the planet. You will find, as many European overlanders do, that even though their truck is sold in a market, their European version often requires a special European part. You will get to know the 2-3 week customs dance well. Enjoy the tune. It's all part of the overlanding life.