I just discovered that a canvas painter's drop cloth is great to keep the
inside of your van sort of clean and sort of dry when you are on the road
with a couple of big water loving dogs.   I left the Northwest US during
winter...a large real canvas drop cloth was spread out over my bedding and
sleeping area, really really kept the wet dog pollution to a minimum...On a
dry  day it can be spread to dry or when wet, just stuffed away folded up
till it is time to dry it, or spread it back over your interior to save the
dry...The doggies have good footing on the canvas and it doesn't stink like
plastic...would make a nice awning, if so inclined..