My recommendation is to use/contact RV Inspection Connection. They have NIRVA certified inspectors nationwide (or whom can otherwise travel to any customers location). In terms of cost, I suppose most depends upon 1) the type of coach to be inspected, and 2) the level of inspection you want to have performed as there are options available such as having all fluids analyzed (which I recommend also).
INSPECTION COST: In terms of cost, and only as example: we paid $1,600 to have an inspection performed on a 2014 Newmar King Aire in Texas which included the sampling analysis of both engine and generator lube oils, coolants as well as the transmission and fuel system. The physical inspection RVIC performed on our behalf took 2-full days to complete and required the coach to be connected to shore power, fresh water supply and sewer dump (so that they could inspect the working condition and performance of those system. Don't be alarmed by the cost above as it's determined by a number of factors which may or may not apply in your case. Best just to call them and inquire.
INSPECTION REPORT: The report RVIC provided us following the inspection was somewhere up to 85 pages in length including accompanying photographs of all major components and/or systems inspected together with an overall executive summary with ratings for each component. The fluid analysis lab reports took an additional 3-5 days but equally came with both detailed reports and summary ratings. All easy to read and understand.
PROTECT YOURSELF: Also, bear in mind that RVIC's NIRVA certified inspectors must agree to and sign annual no-conflict agreements which ensure their customers of no collusion between the inspector and the seller. Something to strongly consider when reaching out to an independent or local RV tech or the like to do a PPI as they may have an undisclosed or prior affiliation with the seller that would not be in your favor. There have been reports of some "shade tree" inspectors actually charging a fee for their services then at the same time, getting paid through the back door by the seller. Unfortunate but true. This of course does not apply to all independent RV inspectors but its still something to consider when looking for an inspection service.
OUTCOME: After receiving and reviewing the RVIC report we "walked away from what had previously appeared to be a great deal" as the report indicated there were a number of underlying problems that we would have never known existed at the time, i.e. high phosphorus/calcium deposit build up in the engine & cooling system, abnormal generator engine wear, faulty ABS system, and a number of features that were not working properly, etc. etc.
Hiring RV Inspection Connection was the right choice for us and "Money well spent!".
FREE CALL: Give them a call, as I'd suspect there is a high probability the have inspectors close to the Orlando area.
https://rvinspection.com