We fish... alot. Our non-winter camping trips are mostly fishing with the boat. If we're staying more than one night, the camper comes off.
With that, backing with a boat and a camper on is only a small difference. On a long boat launch, because our current boat is narrower, I just have to weave a bit more. There's a trick to backing straight up with a trailer you can't see. Try backing an air compressor with a short wheel base that is 3' narrower than your rig...down a city block. Camera's are a bad idea for backing other than checking for kids. Backing accidents happen because folks aren't watching their mirrors. If your watching the camera, you're not watching the sides of the truck.
The weave is light and controlled....it's how one keeps track of where the trailer is and brings it in straight when needed (at the water).
Camper on an incline? It's not going to tip over. It's a boat ramp, not a cliff.