A high , centered rear view camera was the best mod we made. We got a single camera from Tadi Bros. They have excellent customer service. Its wired to the trailer's internal 12v lighting system, so the camera is always on and transmitting wirelessly to the TV monitor. The display screen has those green/yellow/red lines just like in a typical TV backup system. I have my camera tilted so I know how much passing clearance I have using the colored indicator lines.
The monitor replaces the rear view mirror (in a way) I only look at it when 1- we want to change lanes, 2- Heavy traffic and we are crawling along, 3- backing up into a campsite, 4- backing up every place else.
I got over the fear of drilling through the pretty, smooth, clean, pristine, non-leaking fiberglass wall to run the power cord. Tadi sent a rubber grommet, but we used a siloxane waterproofing caulk from work to seal the hole.
To keep the lens clear, I jammed in a piece of foam backer rod between the camera body and the awning. Its been in place 6 months an not a drop of rain or dirt yet.
It works perfectly and give me great comfort when driving down the road knowing I am not going to crush the car in the next lane, back into a tree limb or bollard, and can see pedestrians and veehickles in crowded parking lots.