First the outside perimeter. Ok, let's get it on the table, do not use bales of hay to surround the rig.
Why, they're are cheap and easy to stack?
Because of FIRE, rodents, and bugs. If for some unknown reason the hay should catch fire there would be little chance of survival. And don't forget that many outdoor creatures would love to come inside your RV and spend the cold winter months.
What can be used? You can use skirting for your specific RV. Which is shown below;
Following is a sample of a clamp on a lamp base.
Something I have used is DampRid in closets and drawers where moisture is not wanted and maybe harmful to the contents of the surrounding area.