From my point of view, I will say that even a coach that is this new will have a lot of catch-up maintenance to do.
If you take this on, not necessarily a dumb move, start a maintenance book right away. In the Vintage RV world we have a saying,"If you can't prove it has been done, it hasn't been done."
A vehicle that is that old (past about 15) will need:
**All the rubber replaced or at least carefully inspected. This means all hoses, not just coolant, but brake, fuel, hydraulic and air lines too.
**The cooling system flushed because the corrosion inhibitors are all gone.
**The brake system flushed because the fluid has absorbed moisture.
****Note - these last two when done along with the rubber replacement are kind of "self done".
**A complete lube service. This is something you should learn to do.
You will have to approach this like you have a 20+yo truck carrying a 20yo house that has been in a 15 year long earthquake.
Can this be done? Yes
Can you do it all? Yes
What will it cost? Depends - if you are a capable technician, ~1K$us
If you pay someone to do it --- probably 2~3K$us
Wondering if you can do it? If you are literate and can read the service books you will be ahead of the guys you would probably at World Camper. And, you will know it got done correctly.
My POV?? Our coach has 70+K on it and is out for the 15th season. I do everything it needs. She is over 40yo and still going strong.
Matt