What's this thing really worth?

Personally I wouldn't buy anything with water damage. While the roof was repaired, was the ceiling, interior walls, and/or floor? Mold can grow and water is pretty damaging to RV materials. Water leaks often cause damage you can't see. Also, as others have said, low mileage is actually bad. Rv's need to be used. Seals, hoses etc all dry out from lack of use and it's really bad on gen sets to sit. So In my opinion, a 20 year old entry level class A with low mileage and evidence of leaks, isn't worth much and you risk putting more into than it's worth. Money you will never get back out of it. If you are looking for an RV, get a budget, find floorplans you like and go from there.

BTW, this advice is my opinion and worth exactly what you paid for it. :-)