My solution was 4 - 55 gallons drums with lids that I had sitting around. An undamaged drum (no dents) can hold a lot of weight! I stand one up at each corner of the camper. On top of each drum I placed some short sections of 6x6 timbers I had, aligned with the edges of the camper. This allows me to just leave the camper at the correct height to reload it onto the truck (my electric jacks are old and struggle). To be on the safe side I do run the camper jacks down so they just rest on the ground - not holding any weight but for stability. We have a lot of earthquakes here in Nevada!
