I've said it before in similar posts. An RV of that vintage and mileage will have problems. Lots of problems. There are too many different systems on board that can go wrong. Not necessarily due to abuse, but simply from age deterioration. Heck, just the fridge can cost $1500+ and that is for a small one.
I would opt to buy a newer RV. A 26 year old RV has basically exceeded its lifespan. You can spend the money on restoration, or spend the money on a newer RV. Either way, you are going to spend the money.
Its not an RV...It's a part time job.