I did exactly this! Bought a used NV2500, went to town. Took 7 months to build. Have closets, cabinets, cooktop, sink, wood floors, butcher block counters, fridge, electricity via solar, bed, etc. etc.

I knew nothing about insulation, wiring, woodwork, power tools, etc. and learned everything as I built it.

Was not cheap, because I didn't want to give up any luxuries, so breakeven is in a matter of years, not months. However, its been treating me well. I have spots that I prefer in South Bay and in San Francisco depending where I'm working out of.