Check the hangers to make sure they are not bent. Check underneath for any cracks in the frame.
Look for buckling and fiberglass separation. Run your hand along the whole outside. Open every cabinet and check the ceiling for water marks- signs of past leaks.
Double check all the appliances and air conditioner.
Walk on every spec of floor to make sure it does not " give " anywhere.
Did they have animals? Have your wife get down and smell the carpet in a couple areas.
Verify pin height compared to your tow vehicle.
Other than the other obvious things, like the tires ( that you should replace ), plan on repacking wheel bearings, and checking the roof very well, that's about all the extras I can think of.
Good luck!
