I tried to build systems in my rig, CON KSO, that were easy to service and replace- I didn't try to overthink things. If that sounds interesting to you, here are a couple of ideas for you:
I bought my water tank from Tractor Supply- it's an herbicide spray tank that farmers mount to their ATVs- it came with a pump and clamps to hook to a battery. It was cheap and it works well- it's deep Baja tested surviving multiple three week trips to southern Baja. I think it's twenty or thirty gallons. I've found that for two girls (er... women, actually) and me, it lasts about ten days. They take showers every day. I run it through a 120 buck on demand hot water heater and it works perfect.
We use an ARB 12v fridge in our rig- it runs off a 120ah battery I jammed under the hood. It's the same battery that starts the truck. All kinds of people will tell you not to do it- we've used ours for three weeks at a time, again, in southern Baja and its never been a problem. In fact, we've been using it for short and long trips for about a year now and it's never let us down. We top it off daily with a 120watt Zamp solar panel that's portable and comes with a controller attached. It would be nice to have the solar panel permanently attached to the roof racks but that takes up valuable hang out space up there. The portable system is painless to set up and works perfect.
And hit Baja in winter Dec - February that's the best time to be down there. Cooler nights, perfect temps during the days, warm water down south and the Seven Sisters (If you know, well- then you know).
I'm in SD hit me up when you get out this way- Acheateaux knows me.