If you’re not a DIY fixer, I’d recommend not buying anything that old. RVs always need regular maintenance and fixes. Based on the very low mileage I’m guessing it’s barely been used or moved. Things will rot from underuse. Rodents may have chewed through wires. The house battery is certainly dead unless they’ve replaced it. Has the generator been maintained? Have you tested the holding tanks? Have you inspected the roof for leaks (20 years of sun can do alot of damage). Have you tested the water heater, furnace, air conditioner? Depending on location, rust could be an issue. If you watch TV, it may not be able to receive over the air digital signals without a converter box.. Over the air analog has been discontinued for some time now
In 2017 I purchased a 2008 motorhome (about 9 years old) and it was a never ending nightmare and I was able to do much of the work myself. I had to have a new roof installed for about $16k and it took 3 months. I spent more time working on it than using it. Many lessons learned which was helpful when looking for its replacement.
Many campgrounds don’t allow RVs older than 10 years, especially if they haven’t been kept up well (paint, decals, etc)
I don’t think this is a good first timers rv. If you have a lot of experience and know what to look for, maybe it’s ok. Otherwise you’d be well served to look for something under 5 years old