Hi Kathryn --
Definitely get the van itself checked out, just like a used car.
To source a local mechanic, when I was on the road for 10 months I relied on the Mechanics File http://www.cartalk.com/content/mechanics-files
of listener recommendations/reviews at the website for the NPR show "CarTalk" (Tom and Ray Magliozzi). It always turned out well.
Note that many mechanics are not open on Saturday, so arrange the inspection accordingly (I got caught out on this when I bought my current van three years ago; my only open choice in the rural county seat was the Ford dealership which was open until noon.) As noted above, ask about prior service records if possible. The dealership (Ford or other) can check to see if any recalls are outstanding.
For the SMB components, if there is a fridge may I suggest:
- Ask the seller to cool the fridge down before you arrive (to prove it cools properly).[/*:m:3otx3o8j]
- when you get there, check the fridge (bring a thermometer to toss in there if possible). Then, if s/he had it on 110V switch it to 12V, continue with the rest of your visit/discussion[/*:m:3otx3o8j]
- finally recheck the fridge to make sure that it indeed cools/stays cool on 12V as well as 110V.[/*:m:3otx3o8j]
This is the only thing that I can think of that will take cooperation of the seller, arranged ahead of time.
If the van has a PH house, make sure you can lift it. This is a matter of spring adjustment: the more easily it goes up, the harder it is to bring down. This is something that SMB can adjust, so it's not a deal-breaker -- if you can take the van to an SMB location. Other folks on the forum may be able to chime in here.
Good luck, and have fun!