First, you are looking for the structure of the house to be sound. No damage from water leaks, no rotten wood, no major collision damage. Rebuilding the house can be a big budget item, even if you have the skills, the materials can add up quickly to a lot of money.
Second for me, plumbing (fresh water, waste, LPG) intact and working. Same for electrical, you don't want to be digging into walls to re-wire something damaged or burnt out.
Appliances like range, furnace, refrigerator, water heater, and systems like water pump, DC converter, storage batteries, you want to know what is working, and for what isn't, how much it is going to cost to fix it. Air conditioners and generators, if it has them and you need them, are big ticket items to repair or replace, even when shopping used.
Midas was a fairly well made RV, if taken care of over the years could be still functional after 35 years.
