It's 20 years old and only 35,000 miles so that's either approx. 1500 to 2000/year of driving and a couple years of driving it or sitting unused for many years.
Take it to a qualified mechanic for a complete checkup including oil analysis, belts, brakes, etc. Test the generator. Check the date on the tires. They might be originals - 20 yr. old!!
The actual RV parts should be o.k. - refrig., air conditioner, furnace because that's not much use but definitely check them out.
Also, fill the grey and black tanks with water and make sure they dump o.k. and there are no nasty obstructions from non-use and drying out. You'll probably have to run it to a dump station somewhere nearby unless he could dump in his sewer opening at home.
Check for water leaks inside at the ceilings and baseboards and look in the cabinets. Get a ladder and inspect the roof itself.
This could be an excellent find but check it out thoroughly. Good luck!
Full-Timed for 16 Years
.... Back in S&B Again
Traveled 8 yr in a 40' 2004 Newmar Dutch Star Motorhome
& 8 yr in a 33' Travel Supreme 5th Wheel