Guys,
Thanks for the input! These are all great ideas and valid input.
I did consider mounting the camper backwards for the reasons cited. If it had a side opening door we might have done that. A pass through can be handy, even if you just use it for passing drinks, food, etc. We had a crawl-able one for our proof of concept rental and found it handy for that. In our set of compromises we chose to keep the camper as stock as possible, so no cutting of doorways or passages for this one.
We also considered mounting the camper in a traditional position over the cab, with the bikes stored on the bumpers or behind the camper in some way. With the integrated camper jacks it wouldn't be a big deal to remove it for cab tilt (assuming the chassis was functional enough to drive or roll it forward out from under the pivot frame/camper). The owners I've spoken with have indicated it is a fairly rare requirement to tilt the cab. But, height would be extreme with that design. We'll end up at around 12' / 3.66m as it is, and I think that will be a pretty limiting dimension where we tend to end up.
As to an exterior bike mounting position, we found that simply covering our bike whenever it was parked was a fantastic deterrent to tampering/theft/etc. The only time in over a year of global travel that we had anyone mess with our bike was when we left it parked uncovered in front of a national guard post. The bored soldiers apparently couldn't resist checking it out and tipped it over when they tried to sit on it and the alarm scared the p@## out of them. Out of sight really does = out of mind in most of the world. So, given that experience, we feel keeping the bike(s) under wraps is a good idea. We also know that anything that makes the bike(s) a hassle to mount and unmount like a fussy cover will keep us from riding them. Our goal is to design a clamping/ramp system that will allow extraction from the garage in a minute or so.
Scott hit on the real sleeper issue: weight. Our weight will probably preclude a single rear wheel conversion due to tire weight limits. We will be at or close to GVWR with this thing and the thought of extracting a 12-14k vehicle is humbling for me, whether up to the axles in mud or high centered on a rocky two track.
Another sleeper issue with this chassis is ground clearance. It's not all that much under the axles due to the small wheel size. While we plan to have our fabricator build bash plates for critical components, we won't be able to take on the more radical terrain if it requires high ground clearance for passage.
The people that we've spoken with who have taken these rigs around the planet have told us that they've never come close on departure angle (with the exception of one ferry in China), so it may be less of a limiting dimension than we are thinking right now.
In the end, the rear axle position will be determined by a delicate balancing act between weight balance, turning radius, departure angle and as you've pointed out, break-over angle. The front axle capacity of 5,730 lb / 2,599 k will probably be our limiting factor.
I agree with Scott that turning radius is a very, very precious commodity and one that I will guard jealously and sacrifice grudgingly.
One thing we learned with the proof of concept rental is that a long overhang not only limits you with departure angle, it also creates a huge aft-axle swing/sweep that can be equally limiting in the typically tight environments of developing economies.
We will, no matter where we place the rear axle, end up with a vehicle that will be large by developing world road/village/bridge standards, and we must be pragmatic about that and develop / adapt an exploration style that takes that reality into account. It is our hope that having the bikes will mitigate the inherent limitations of the rig. It is also our hope that the living space, comforts and carrying capacity provided by the rig will enhance our 2-3 years of exploration.
But as they say, hope is not a strategy...
Please keep the observations, suggestions and critiques coming. We can use all the help we can get.
Doug