Look for what you can't easily "see":
-- A "clear" title (not "salvage"). Make sure it was not in any kind of prior damage (accident, flood, etc.).
-- Dates/records for any prior service that was done on the unit. If you can't find any, put a full chassis/house service into your budget before you really go anywhere (i.e., fluids and filter changes, etc.).
-- Look for excessive rust underneath; delamination of sidewalls; slide outs correctly working and sealing tightly shut, etc.
-- Go up on the roof - check for any prior physical damage (or former damage repairs), check seals around perimeter and around anything else that's installed up there, check for any evidence of leaking or cracks (same with around windows and windshields).
-- Make sure heater works and air conditioner is actually cold
Also, try out every switch, knob, tank, button, or lever!
Best of luck -- I LOVE those Revolutions!
2016 American Coach Revolution 42T
2004 Jeep Wrangler Sport