No specific problems with these in general. So it is nearing 20 years old now, if it is still rolling it is probably worth the price. Pop ups are dead simple, and this era was well built and didn't have a lot of the fancy do-dads that fail nowadays.
First, check the date code on the tires to see if they are safe. Also test the brakes to make sure they are working. Make sure that the top goes up and down without any issues. At this age you will probably have to do some work on it, but you want the basics in place. I would probably expect to need to replace some of soft surfaces, and I would look carefully for signs of rot or mold. After 20 years, there have probably been a few water infiltrations, but have they been dealt with promptly? Water stains aren't necessarily an issue, but extensive soft wood is.
I would have the furnace checked by a pro if you are planning on using it. After 20 years there's a pretty good chance the heat exchanger will be leaking. Also, try the fridge on both propane and 120V (I would never use it on 12V - that's a battery killer). Check the water heater if you care - we never used ours because we just boiled a kettle for dishes; it takes a lot of propane to keep 6-8 gallons of water hot all the time and we usually camped our pup without hookups.
Note if you do plan to boondock, that era had incandescent lighting. Get some cheap LED replacement bulbs on Amazon your battery life will thank you.
Hope it works out for you! Welcome! And if it does work out for you, come back often. Lots of experienced owners here who have done and see it all.
