MPG:
We full-time live-aboard our ExpeditionVehicle.
We rarely travel more than a hundred miles a month.
Fuel is a very minor part of the budget.
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Sturdy Construction:
We chose our foundation vehicle for its common components availability in the Western Hemisphere.
Cummins 8.3 mechanical (no computers), Allison 3060 automatic.
Over two decades full-time live-aboard, our only repairs were replacing the radiator.
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We also chose our vehicle for its commercial 'million-mile' heavy-duty chassis.
Our GVWR -- 29,000#.
Our weight across the scale -- 14,000#.
Our cargo capacity -- about seven ton.
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For our purposes...
...up rough logger tracks to remote mountain lakes, and
... across trackless desert to isolated Baja beaches...
... we need excess ground-clearance plus the ability to roll over minor obstacles in the road.
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Getting Started:
We suggest crafting your RequirementsStatement.
This might include souls aboard, destinations, full-time/a few weekends annually, camping experience, mechanical abilities.
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For example:
Number One in our RequirementsStatement -- 'holding hands while watching the sunrise'.
Number Two -- 'boondock exclusively, no resorts nor campgrounds'.
Also in there someplace -- 'caravanning with experienced travelers'... our caravan chums have home-built rigs instead of factory RecreateVehicles.
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We agree with your 'do not need much'.
Acquire a suitable candidate, toss in some car-camping gear, go have fun.
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[edited to add]
Our introduction with plenty of portraits, plus our reasons for our decisions:
https://vanlivingforum.com/threads/expeditionvehicle-build.44908/#post-576110
