I got one of these with a 10″ screen and 4 wireless cameras for my old RV. Had 2 below mirrors, one high back and oem pointed down so I could watch hitch. The 4th was on my trailer back.
I ripped it out when getting a new coach and plan on doing the same thing as you. Before I had issues with the cam on my 16ft trailer back getting solid signal so used a wireless antenna extension cable and ran the antenna to the front of my trailer which helped a ton. When adding to my Prevost I plan on doing the same with the antenna on the screen and running it all the way to the back roof of my coac
I just wish I could find these types of cameras with an hdmi out and no screen so I could switch between cameras but use a larger screen as ill be putting 24″ monitors above my windshield.
Also it has an option to split screen any 2 cameras so the sel button switches from all 4 screens and 1 split. Wish it had a 2nd split option so I could have L/R while driving and both backups while backing up
https://a.co/d/89tJwZV
One more tip if you drive at night get reverse lights on the trailer and or underbody lights. It’s a lifesaver when backing up or turning at night because It’ll light up the road under the trailer so you can see if it’s pavement or curb or what.