I'm doing something similar. I have a TRENDnet SecurView wireless internet surveillance camera, model TV-IP110W, mounted to the inside ledge of the rear window with Velcro. It is plugged in to the inverter circuit below the dinette. Whenever the inverter is switched on, the camera comes on. I have a Linksys wireless router on the sofa midway along the trailer. It, too, is plugged into the inverter circuit and comes on whenever the inverter is switched on. The router is set up as a local net with security on. I have my iPod Touch in the cab of the TV plugged in to a charger and on all the time. It is connected via the Linksys wifi to the camera and displays a continuous picture outside the rear of the trailer. It is full-color and real-time. The image is a bit jerky, but is effective for backing up and for monitoring traffic behind me.
The last thing I do when we leave a campsite is to turn on the inverter, which then automatically activates the camera and router. Presto! Rear-view camera and no wiring between trailer and TV.
2010 25' International Serenity
2010 Toyota Sequoia
WBCCI 2515, TAC VA-9