I think that basic is better, whatever your vehicle. More bells and whistles = more things to go wrong = more maintenance $.
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This's our experience, too.
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2003, for our ExpeditionVehicle, we built with:
* zero plumbing
* two 12vdc dual-outlets along each wall.
We have zero built-in water pumps and zero hidden tanks concealed behind zero built-in cabinets.
We have zero built-in 120vac.
.
Our heater is modular, usually stashed out of the way.
Our kitchen, same.
Our shower, same.
Our several inverters -- multiple, cheap, easily replaceable.
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What else... zero heated floor, zero forced-air furnace, zero entertainment-center with optional wine-chiller and electric fireplace 'up-grade'.
Hardly any chandeliers or marble countertops.
Somehow, we manage to manage without a heated towel-rack awaiting our exit from the recirculation soaking-tub.
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We engineered our rig after a half-century of make-do camping in lesser rigs, perpetually fixing their equipment.
Between fixing equipment, we worried about the next equipment failure, fluids soaking the carpet and upholstery, unscheduled explosions and odd odors suddenly requiring a hasty evacuation while speed-dial Trained Perfesserionerals were consulted.
And that tends to harsh our mellow.
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The kicker:
* No! Holes! In! The! Roof!.