At 43,000 miles the chassis is barely broken in if properly maintained, but the house is 10+ years old and needs continuous attention even if not used. So you need a RV expert to look at it, mor than a mechanic.
Greyhawk was Jayco's mid range motorhome in 2004, fitting between an "essentials all included" Escapade and a Granite Ridge with "luxury" interior furnishings. No better, no orse than other manufacturers' mid-range lines, but recognize that many in that era used mid-range as their entry level,as did Jayco before and after the years they offered Escapade. All Jayco C lines were made on the same lines using the same production methods in 2004.
You want it to have no damage from long-term water leaks, and no leaks now. Other than structural damage from leaks, most other issues tend to be minor. If you plan to use the generator, make sure that is working, as they tend to become a problem when not regularly used. I have two friends in my RV club who have never run the generators in their C's, peroid of ownership three to five years, and have no confidence that the things will start. That is one component that tends to be expensive to repair, because the work usually has to be bench for access, and remove/reinstall labor can be high.
Tom Test
Itasca Spirit 29B