I have a wired camera. One wire (cable) from the camera, down the ladder, under side of the TC overhang op to the front of the TC/bed of truck. A second wire from there to the truck sliding window, under the back and front seats up to the monitor. The monitor has one wire which plugs into the cigarette lighter. On the sliding window, I put a strip of foam insulation to close the gap. When I unload the TC, I unplug the single wire at the front of the TC/bed of truck. I really do not see how it could get easier than that.
On my wife's Toyota, I had to disassemble the taillight, and run wires to the camera. Sounds simple, but it is easier to say than do. The monitor install is very similar to the truck. The reception has so much interference, inconstant picture, that she simply unplugged it from the lighter after less than a month. It would arbitrarily come on while we were driving down the road, no picture, just snow.
The only way I would buy another wireless camera is if I had no other choice. It took me about 2 hours to install the wireless in the Toyota, and less than an hour in the TC with the wired camera.
I use my camera all of the time. It works far better than my extended mirrors.