mpruet said:
You really need to do two inspections.
1) chassis - which would include the engine and frame. You would probably need to have a mechanic for that. I would also use a pressure washer to see if there are any leaks at any of the seams and/or windows.
2) interior - This would include all of the appliances - Does the water system work ok? What about hot water heater? Is the water pump working ok. What about the fridge? Many older fridges will need to be replaced, especially if it runs on propane. What about the heating system? You need to test everything. A class-C that is 20 years old will probably not run all of the interior appliances very well and you might need to replace some of them.
Agree with #1 ... also check the entire front brakes and if you're having a mechanic look at it, make sure the front end components are ok.
Also, check the date on the tires. There may be lots of tread but cracks or crumbling rubber due to age/UV exposure. 6 new tires will cost ~$1200. Ck the chassis and coach batteries with a multimeter and if the batteries are the ones you need to add water to, check the cells with one of those turkey baster looking things. There's a good youtube video on that. 3 new batteries will run you about $500.
Agree with #2 as well ... check the water pressure in the kitchen and bathroom sinks to see if the water pressure is good.
See if the genie starts right up. Ck for propane leak with a spray bottle that has water/dish soap. Ck the condition of the awning. Ck the condition of the "glazing bead" that goes around the windows from the outside (a fairly easy and inexpensive repair but could show possible water damage areas if not properly maintained).
See if the owner will allow you to take the rig for a ride up a hill and see how the engine performs.
These are in addition to everything else in the other posts. If you really want this RV, negotiate price based on what you find.
I bought my Class C (Forest River Sunseeker) about 3 years ago. I looked for an entire year for the make, model, mileage, condition, approx. year and at the price I wanted to pay. I got very lucky and am still happy with my choice.
Good luck OP! Let us know how it works out.