I pulled the Lance manual for recent TCs, and it said that the camper was fine on the jacks once lowered into place from the truck. However, I like having fairly wide jack pads for all jacks (to mitigate shifting/sandy/unlevel ground.) I also think it wouldn't hurt to have the weight on the center part if the camper is going to be in the same place for a while, so three sawhorses from Torklift (Camper Packers) might be a wise idea just to distribute load evenly across all jacks and the bottom.
Of course, the $3000 for a Stable-lift system seems to solve all of these problems.