Mine has load range D tires. When the camper moves, its the side walls of the tires flexing. Short of putting it up on blocks, the only thing I feel that will help is the locks like in post 3 (or switch to range E tires).
I have sissor jacks on the rear, and a 2 legged thing I put under the hitch, plus a BAL jack between the trailer tires on one side, plus a custom tire chucks I made out of 6"x6"'s that has a bolt and wing nut to tighten them up between the tires.
My last camper had smaller tires, but they were load range E, and had less movement.