It sounds like your TV is quite adequate to tow the TM. The TM is really easy to tow. Backing will just take practice. Go into a vacant p/lot and go slow.
NADA value is under $8,000. I'm not sure where they get their figures but that seems a bit low from what I've seen (and I've seen a lot). Although $10K may be a bit high unless the TM is in "Like new" condition.
http://www.nadaguides.com/default.as...T&gc=RV>c=TT
Here's a good search site for TMs:
http://www.oodle.com/vehicle/-/make_trailmanor/?s=price
Just remember, the prices listed on this site are "Asking prices" not "Sold price".
What area do you live in?
The AC unit that comes from the factory is usually a 7,000BTU unit. From what I've heard, they are fairly inadequate. The good news is, they are easily replaced with a 10,000BTU unit for under $300. If you get to that point, shoot me a PM and I will send you pics & tips on the upgrade.