About drilling holes?
On my Montana, to put the side cameras in the same spot as the yellow marker running lights, the door for the propane tank interfered with the camera vision. In order to get around that, I decided to leave the original lights where they were and mount the camera with marker light up higher so it would clear the view of the door hinge.
In order to do so, meant drilling holes in the wall of the camper. Fortunate, the open space for the propane tank compartment provided lots of room to reach the wires and such.
To drill the holes, I placed the camera/light in it's spot and then market the wall with a pencil. I also added marks for the screw holes. Next I drilled all the holes with the absolute smallest drill bit I had to get through the outer layer of wall (the fiberglass). I wan't concerned about the inside of the wall since it was wood (or Luna) and the middle of the wall is Styrofoam.
I then drilled with a slightly bigger bit so the screws used would catch, but not break out the fiberglass. The hole where the wire was to go through was drilled out about 3 times, each time, getting a bit bigger and bigger until it was just big enough to fit all 4 wires through.
To install the actual camera/light, I put the wires through the wall, added a dab of putty around each hole to seal them up and then added putty under the light that actually touched the wall. Then screwed the camer/light in place. Next, attached wires inside the compartment (I spliced into the existing wires that ran to the original light). And then finally, attached the camera fixture to the light (as this is done after the light is affixed.). Last, put the lens cover back on the light.
It looks like, over the door, you'll need to catch the wire that turns on your porch light. Then to activate the camera, you'll need to leaver your porch light turned on.