I've been thinking of the same thing. I don't like sitting it down or picking it up off the floor. Gotta be careful with the back these days.
In my new garage, the camper is going to sit so close to two walls that I wont be able to use that wall space for much of anything. I've been thinking that I would make sort of a narrow shelf for the tailgate to sit on, and attach it to the wall at the right height so I don't have to bend over to pick it up or sit it down. The tailgate will sit in the shelf standing up, the way it's mounted on the truck. I'll probably have to secure it with a bungy cord or a strap so it won't fall over.
Either on the wall to the side.......

Or behind the camper.

On edit: Actually, it might make more sense for me to put my shelf up here close to the garage door, where the end of the truck will be just before backing under the camper. Less squeezing around between the camper and the wall with a heavy tailgate in my arms.
Yeah, that's the ticket! :C

:):)