According to an old TM brochure I received from a fellow board member, the dry weight of a TM 26 is about 2560 lbs. When you add your stuff & propane tanks & water & etc. it will weight much more.
Price seems a bit steep to me.
In this age of a trailer, I'd pay careful attention to the corners and shell edges where wood rot can be a problem. Here is a link to a bunch of threads on what to look for in a used TM:
http://trailmanorowners.com/forum/showthread.php?t=8878
Those posts should keep you busy for a while, lol!