John,
I use Property Damage Appraisers (link:
http://www.pdacorporation.com/) when I purchase something like that. Go to their website and look for office close to them and give them a call and tell them you would like to hire them to inspect this vehicle and get a full report. Unbiased and they will take a lot of photos and check for such things as previous repairs, etc. I used them for last motorhome purchase as the motorhome was in Harlingen, TX. which I couldn't find anyone I knew on on the boards to look at. I was very pleased with the inspection.