Congratulations on hitting the road!!! Have fun!!
A question..If you put slide supports under your slides and the groud is soft and the trailer settles will your slide supports settle the same...Don't think so. Now if you are going to be on a concrete pad and there will be no movement up or down in the soil I wouldn't hesitate to use them, but I don't think that it would be good for the slides to use them on soil.
Just my opinion