It is basically a project to take a Toyota 4x4 pickup and turn in into a Micro RV with limited rock crawling abilities. The RV back, replaces pickup bed, would be near the same width as the cab, but extend up a 18" to 24" above the cab's roof height. Length may be extended a bit to get it so I can have about 7' of bed length for sleeping. Right now I'm in the design phase exploring options and wacky ideas for the back. Most stuff like the bed and storage will be removable and reconfigurable. Some stuff like heat and AC will be built in, but in a way they don't interfere with putting stuff in back. Also the 12VDC battery bank and 120VAC inverter will be built in as they could be dangerous if they moved about. When I'm not camping I'll be able to throw tools and fencing supplies in back and go out repairing fences on the farm. Having 120VAC will allow powering saws, drills, etc..

As for the Micro RV's exterior shape. I do feel some concessions for efficiency can be made, but as to how much I don't know at this point. One of the main issues governing efficiency of a body shape is the overall cross section being pushed through the wind and how the air is displaced in front. I can't control the cab's shape so I'm mostly stuck there. Also I want more height in back than the cab's cross section allows for so I'm adding some more cross sectional area with the 18" to 24" height increase. I can make the transitions from the cab to the back smooth, but that isn't much in relationship to the overall air drag. What is left is trying to bring the displaced air back together at the rear in a manner that produces the least amount of drag. That pretty much leaves smooth gentle curves from the widest point to the rear end and making that rear end with about half the cross sectional area of the widest point. Unfortunately that would cut into the already limited interior space and make that space non rectangular. Hence I likely won't do anything with it.