Way too much worry and consternation. I would not buy used out of the chute. You do not know what to look for and wouldn't recognize it if you saw it.
There is nothing but experience that will make you a confident operator,but there are millions of us managing to get these things from point A to B with out leaving a trail of destruction.
To me the "secret" of towing is to be cautiously aggressive. Unabashedly takewide right hand turns. Position yourself where you need to be on the road. Other drivers either don't understand or don't care that you have space and weight considerations. Drive your own drive and let the other sort out their own problems. You are large slow and have a perfect right to operate legally.