Water leaks are the worst as hidden damage can be present. Any "soft spot" on the floor, obvious discoloration anywhere inside especially the roof, caulking that has gapped wide or looks very old(may need replacement) all could be indications of possible leaks now fixed out otherwise.
Check out all systems that you can - with Propane on try heater, stove and hot water tank(must have water in it), fridge, check to see if gauges appear to be working, run AC on 110volt , fans, lights, water pump, TVs including antenna booster, inverter if it has one, move slides in an out listening for unusual noises and watching for uneven pulling side to side. They should all close flush to the side of the RV. Jacks if they have them - test leveling and putting down an up. Look at upholstery and bed to see if wear seems within limits. Try all light fixtures and run all faucets.
Check tires not only for tread but for AGE!! Do an internet search on how to read age of the tires. Anything approaching or over 7 years likely means you will need new tires. Lots of tread does not mean the tires are safe to run on - rubber deteriorates and may be cracked inside the tire. Inspecting from the outside is not enough - check the AGE. Check battery for age and charge level.
Inspect to see ease of access to your services - ease of using dump handles, water inlet, electrical hookup cord access, hot water bypass if it has one.
Storage - where will you put stuff - Kitchen area - pot/pans, dishes, food stuff, paper products and.......... outside chairs, sewer hoses, extension cord, water hoses, and anything else that is essential to you. Beware overloading whatever RV you decide upon.
Try to imagine how any unit would actually function for you. Good luck with the search and keep reading for more ideas of essentials to check out!
