I would pay the money to get it inspected by an independent RV Technician and use his report for bargainging. Also be a good idea to check all of his engine and chassis maintenance records to see if the work was done on schedule. No records, I think I would pass on it.
As for price, check www.nadaguides.com
. Practically RVs are going fro the low end of the low reatils, in good condition. Do not use any add on options to determine the price. With the age of the tire, I would deduct a set of tires from the price.
If it is really of interest, take it on a LONG drive, 30 miles or so and get it up to freeway speeds to see if it handles OK as well as some city driving.
Glad you joined us on iRV2.