I think rental
is an excellent idea. While it may see like money down the drain after the trip is over, it would be a lot better to spend a week's rental than to take the loss of buying a new trailer and having to re-sell it at a loss, or spending time and money fixing up a used trailer which turns out to be unsuitable.
We rented a tent trailer for a week-long vacation trip, and learned that we were willing to tow a trailer, but did not want the tent (pop-up) type. Since I've seen tent trailers sell at one year old with two weekends of use for a couple thousand less than new, this turned out to be a good move.
Recently we are thinking of options again, and I'm surprised to see the range of RVs
available for rent (at least in Western Canada) - from relatively small travel trailers to large Class A motorhomes, with truck campers thrown in as well. While I knew that the truck campers could be rented complete with the truck, it seems that a least one company rents their trailers complete with tow vehicle (large SUV), which makes sense to me since a renter is unlikely to have the right tug already.
Of course, anyone considering RV rental must watch the movie RV
first... or maybe after, so they don't get scared off!