Since this is a Class A motorhome, I'd try to catch the dirt before it gets into the coach. I'd look for a door mat outside at the entrance, or on the entry steps into the coach. If you want something to catch dirt in the cockpit foot wells, you could choose between universal carpeted mats, or rubber/plastic floor mats.
1973 Revcon 220 flatnose motorhome
Olds Toronado front drive with 455 cid engine