I MH was donated to the Purple Heart Foundation and I purchased it from the guy who bought it at the auction. Like you I looked it over but it was winterized so I couldn't check the water systems and the gen set would start but not stay running. Bought it anyway because the chassis was so clean and the house had potential.
I guess I got lucky all appliances worked except the gen set I through a few $$ at. I later realized the frig and AC had been replaced with newer units so the rig was cared for.
I guess it may depend on the charity you get it from. Some charities people use to dump vehicles in poor shape others maybe not.
JKaz