Well being that I got a mention in a earlier post I guess that I should chime in, even if my name was spelled wrong :B
The points that were made by others are valid, the key in all of this is the maintenance of the Chassis and how well and often it was done and documented. I have 28 pages.
As we all know the modern vehicles are made to last a long time, hence the longer warrantee periods of most of them, IF, and that is a big IF they are maintained well and often.
As you can see in the
Link in my signature about buying a rental that more than 25 owners of Ex Rentals have had no problems with High Mileage Well Maintained RVs.
You will find a lot of opinions about this but not any facts to back them up. Only the real owners can tell you about the reliability of a vehicle.
So If you follow the suggestions of Sloop Smitten and others I believe that there would be no reason not to look at a high mileage RV if it was well maintained.
Just check the House part for leaks and other problems that will come along later and be very costly to fix.