Nice mat idea!
Some campsites have spongy areas off the steps, and this would be handy there.
We also use a regular old rubber doormat, plus I cut a carpet sample in half which just fits the two steps inside the Vegas, a short shag like the inside carpet. We have a second set of indoor/outdoor carpet that we use when we are near the beach. Our 2016 has carpet under the front seats, so another sample protects the high traffic area between the seats.
When the ones for the steps get dirty, we throw them out and cut a new one!