If you are worried about putting something under tires a lot of people use those white plastic cutting boards, or cut up one of those plastic things for under office chairs or the lego things or some good 2X12's. They all work.
On gravel the lego things will get small gravel in the crevises.
Nice to have an inside place for the RV; good for you.
I do all my own stunts
03 Dolphin LX 6355, Workhorse W22, 8.1 vortec, 04 CR-V, Blue Ox, Brake Pro----Norm, Barb and
Doc(He's a PhD)