My folks had a Tioga very similar to that one many, many years ago. They are now on their 4th motorhome, and they still say that one was the best.
That said, with something that is 25 years old, it is my opinion that who the manufacture is makes less of a difference vs how the motorhome was maintained.
Stuff you mentioned should be looked at in addition to the date code on the tires (anything over 7 years old is on borrowed time.
Look at the condition of all the belts & hoses in the engine. Be prepared to service the transmission & cooling system.
Make sure all the mechanical systems of the coach function - water, propane, fridge/freezer, furnace & AC, etc.
Thre more service records they have, the better.
I also think that while NADA might be good for bargaining, it really doesn't have much determination on the value and what you will pay for something in that age. If it is better than average condition, it will sell for more.
Good luck.