As with any vehicle that is nearly 25 years old, initial quality counts and Pleasure-way makes good products, but at that age current condition is much more important. At best any rubber parts are likely to be deteriorating, like suspension bushings, window seals, etc. You may get lucky and fine one that has had exceptional care and the aging items replaced, as that is somewhat common, but certainly not universal. Look carefully for water damage, underbody and frame rust, and be sure to drive it in the wind to check the handling. If you do think it looks good and get serious, and good mechanic for the van parts should check it out, and an RV guy for the RV systems, unless you are completely up on all that stuff.
I drive an 1996 car, so I am certainly not afraid of old, just cautious, and it has been a very good vehicle for me for over 5 years already and it hopefully a lot more years.