Look for a mobile RV tech in the area. You pay them their standard hourly rate and can usually agree on a fixed amount of time you are willing to pay for. I'd say 1-3 hours, depending on how thorough you want them to be. Give them a checklist of things you want tested or checked out.
You may also want a chassis shop to check out the engine, tranny, suspension, etc. That's separate and harder to arrange, since it has to go to the shop.
Former owner of 2004 American Tradition and several other RVs
Home is West Palm Beach, FL