Since you are an experienced RV'er, then you know all the systems that need to be checked. I'd look around the ceiling edges and around roof vents to see if it has leaked any. I'd also check the tires for cracking or uneven wear and it might be due a wheel bearing lube job.
I'd agree with you though, there's no way I'd pay a dealer $795 for a unit I was buying from him. What a crock!
2013 Jeep Grand Cherokee
2013 Coachmen Freedom Express 233RBS
Prior: Jayco Pop Up, Shasta Bunkhouse, Rockwood Pop Up