Like others have said condition is everything, the photos are far too few, and far too low of resolution to really tell much, a few good signs that it may have been well cared for are the tire covers, windshield protectors and the fact that the faucets on the sinks have been replaced with higher quality domestic models. So this one may be a rare find, or may be a money pit, depends on condition (rot) engine, maintenance, age of tires and batteries, ... It is real easy to spend $5,000 or more on maintenance even on coaches that are in relatively good shape, at this age all of the rubber components should have been changed out at least once, this includes belts, hoses, suspension bushings, probably also shock absorbers, rubber brake lines, etc. The ad mentions new air conditioner, how about the RV refrigerator, 20 years is a long time for an RV refrigerator to last, check the back side of the refrigerator for ammonia leaks as this can be a major fire hazard (look for yellow gunk around the coils and pipes on the back of the fridge under the access panel).
p.s. it has been mentioned before, but here goes again, RV tires generally age out, and rot from the inside after about 7 years, so check the DOT date codes on the tires, tread life is not usually the determining factor on RV's.
