So, you are camping and you want to unload your truck camper

We don't take the camper off often but yes we do on occasion. We just lower the camper down as far as we can and use it like we do when it's on the truck. There are some wobble stop type product made but we haven't seen a need for them.

Your post doesn't indicate what brand the camper is. Most modern campers are designed to be used off the truck with all weight being distributed by the jacks. You may want to verify with the manufacturer of your camper.