Each setup reacts differently. I have decades of experience backing smaller trailers but I had a good view our of the back window. It meant that I had my left hand on the steering wheel right arm over the back of the seat and I am turned so that I can see out the back window. For some reason it was easy for me to back into almost any space but a lot of it is done intuitively. I can imagine where the body of the TV, trailer and all of the tires are regardless of the direction, turning L or R or speed.
[font=Tahoma,Verdana,Arial,Sans-Serif]I have a 2003 Ford E350 and tow a 29' [/font][font=Tahoma,Verdana,Arial,Sans-Serif]1976 Airstream[/font][font=Tahoma,Verdana,Arial,Sans-Serif]. [/font]11 years ago I had to learn to back that set up into a space and it was not easy. After about the second year I felt more comfortable backing the 29' trailer with mirrors and a spotter but I still lose track of all the variables and occasionally have to start over. Most of the time I have no problems but if I have been driving for 6-10 hours things don' go well sometimes.
Since the mirrors provide a limited view of what is behind me I often get out and look. Each time I get ready to back up I will jump out of the van and walk back to the end of the trailer. In my case I usually drive 8 feet or so forward of the near part of the space I want to get into and then start backing up but that depends if there are any holes, rocks, other rigs close by, trees, the width of the space, any limbs overhead, or little children running around my rig.
It is the little kids that are the most bothersome. You have no idea if you have backed over one and if you do it is way too hard to pick the little body parts out of the tread. I am sure you have had some similar problems.
Anyway, just start making up ways that allow you to keep track of the trailer and the front of the TV at the same time. Drive slowly and learn to buff out scratches and how you can use Bondo to patch up dents. It helps if you are good with spray paint and can find a two part clear coat in a rattle can.