If you live where campers have a license plate, the truck plate doesn’t need to be visible, same as when towing a trailer.
On my previous campers that had the tanks hanging below the rear I put a piece of 2” thick 4’x8’ rigid foam insulation under the camper to buy a little extra room. I towed a large trailer with the tongue extended to reach the truck under an 11.5 camper without using a hitch extension and it looked fairly tight but wasn’t ever a problem.
As mentioned, spare tire crank can be reoriented and air bag fill valve are easy to put anywhere, I used to have them inside the gas filler door. But - a far better way is to drop the couple hundred $ on an onboard air setup for your bags. It’s very handy to be able to fill and dump air at will, anytime and anyplace.