[Wavery]

As you rightly pointed out, it will probably need 3 new tires and possibly a new battery (5-years is about life expectancy on most batteries).

I would also stop at the closest garage and have the wheel bearings serviced before towing it home (if it's a long drive) unless the owner has proof that the bearings have been recently serviced (don't take his word for it....nice guys are a dime a dozen). If they haven't been serviced, I would obtain a new set of bearings and seals, just in case. They're cheap enough and you can usually take them back if not needed.

Your comment, "a one-owner 2005 2720SL that's been used only a few times" leads me to think that this trailer has sat in storage for long periods of time. The worst thing that one can do to trailer tires and bearings is let the trailer sit for long periods of time.

Sounds like you may have stumbled upon a real jewel here. If you conduct this transaction wisely, you should get many years of good service out of a lightly used 2005 TM.

BTW.......I wouldn't be overly concerned about the caulking if the trailer was garage stored and lightly used. Inspect it carefully before tearing it all out. That's a lot of work and chances are the original caulking may be just fine. Sun exposure and towing stresses are what cause the caulking to fail. Sounds like this trailer may have had neither.