F350 and Northern Lite 10-2

Since my Bigfoot is built similar to NL in that the walls support it, I used plywood and a rubber mat. I think I used 5/8" exterior grade plywood. I cut the plywood in 4 pieces so that it is captured in front of the wheel wells, behind the wheel wells, and in the front of the tailgate opening. May have taken 3 sheets to accomplish. I wanted support behind the wheel wells where the camper skirt is. I put the plywood down to prevent what I thought could be some voids and lack of support of the camper in the truck bed corrugations. I painted the plywood with exterior latex. The 4 pieces are relatively easy to remove and store. I put a full bed rubber truck mat on top of the plywood. The mat is harder to remove and install than the plywood. I usually just slide it out of the truck into my utility trailer.
If I didn't have to remove the plywood and the mat for the 5th wheel hitch, I would just leave them in the truck.