I measured the distance from the bottom of the jack to the ground, and it is 22", when the camper is loaded onto the truck. So the height of whatever method I use--square boards, concrete blocks,etc. will be less than 2' high. I don't see any danger of squares of wood 12" square toppling over when piled less than 2' high, even with 700 lbs of pressure on each one. I have some pressed plywood shelving material I found, and I am going to cut them into square foot pieces and glue them together. They'll never get wet, they are inside.