Looks can be deceiving. Check the outside walls for delamination and the roof and floor for soft spots, especially around the TV antennae mount and ladder fixtures. Look at the ceiling and the inside walls for evidence of water intrusion. Insure the appliances work. Take it to a RV shop that has the gizmo that smells propane leaks. Check the spring hangers for cracks and if you can pull a hub or two to check the brake components. Tires need to be less than 5 years old to be serviceable. The manufacture date is imprinted on the side, but not both sides.
When Thor was still in business I pulled several of them to dealers. They were of typical SoCal RV quality and in case you are not aware, every RV builder in SoCal, except one, is now out of business.