I like the in-bed location, with either type of tailgate.
As for where in the bed, I had mine installed in the rear corner stake pocket, facing forward. If I had to do it again, I would put it in that stake pocket, but facing to the side. I chose the forward facing direction thinking that it would be less likely to snap on cargo sliding in/out of the bed. But it makes plugging the cord kind of awkward. Snagging cargo now seems unlikely and unimportant.
I suggest you have one put in the bed now. You can still use the bumper socket, or the in-bed socket, whichever suits your fancy.