Kayteg has a good point. As much as I thought it would be convienent to have an in bed plug in for the camper, I started out by making a long extension that plugged into the back of the truck with a Y for a trailer.
It's pretty much impossible to unplug a camper plugged in in the front of the bed without lifting the camper off and difficult in the rear of the bed on some/a lot of campers.
So for me the convienence of easily unplugging the camper from the truck when it's parked for a while makes plugging into the back bumper the best option.