I also would accompany on the test drive. I think it would make many buyers more comfortable with the process, and likely you have a better understanding of the local roads than they do. It also makes it harder for a completely unscrupulous person to just drive off into the sunset with their new (stolen) RV.
Watching them get a bank check is nice if there's a reasonably local branch of their bank near you. If there is not, you have rather more limited options. Some may suggest that you not turn over the title until you verify that the funds clear, but that merely transfers the burden of trust from you trusting the buyer to be basically honest to the buyer trusting you to be basically honest--which is perhaps better for you, but not an improvement in the process overall. I know as a buyer I would be rather loathe to hand over my hard-earned money for the promise of the future production of the title.
The buyer, after purchasing the motorhome, should generally not drive it home using your plates. (If you live in one of the few states where plates stay with the vehicle rather than the owner, that's obviously a different situation.) Generally if the buyer is a resident in the state they would need to go to the DMV and obtain their own plates, paying the various taxes and fees and such needed. If they're from out of state, generally there's an "in-transit permit" that can be had for a nominal fee that gives a temporary registration to drive it home. In Minnesota, it looks like the fee for a non-resident temporary permit is one whole dollar.