Try an iBall
I have an iBall camera. No wires needed. It uses a magnetic base to hold the camera in position where you place it, and a cigar lighter plugin in unit with the screen to show you what it sees.
My truck has an aluminum storage box on the front of the truck bed, so I screwed a small galvanized plate on it to hold the camera for the magnetic base to hold.
I also use it on the rear bumper of a truck without a rear camera to help hitching a bumper pull trailer.
iBall 5.8GHz Wireless Magnetic Trailer Hitch Rear View Camera LCD Monitor Fits Any Vehicle, Car or Truck https://www.amazon.com/dp/B0035WSQEC/ref=cm_sw_r_cp_apa_i_ECSfCb0B5X653