Pretty sound advice so far. As you have read it is not how much weight you can tow, it is how much weight you can carry. The cargo weight is vehicle dependent because every optional do-dad on your TV reduced the cargo capacity. The max cargo usually appears on the yellow sticker on the door jamb.
My F-150 4x4 has a max cargo of 1411 lbs. with the options I have. It is maxed out with a 5000 lb. trailer and all my other stuff. Also my previous F-150 had enough cargo capacity but only a 200 hp. motor. The 25 foot TT we rented was a real challenge to pull. That is why we have the e-Boost F-150 now.
New or use you are going to be stuck with the features the TT has, unless you order new from the factory. Most people find floor plan the most important feature, but you have to tow it and pay for it.
If you are new to RVing I always suggest renting a similar unit first, a week of towing will tell you a lot.
Finally without going into details, HD television is the transmission method used the broadcaster and has nothing to do with the antenna. The ability to receive digital and HD is determined by the television set not the antenna.
