You'd sure think RV manufacturers would have a clue regarding aero... but evidently most of them don't.
I had to laugh at an RV I happened to notice the other day... all the leading edges: square as can be. Actually, all the edges on the whole thing- front, top, and rear were all square as could be. BUT the rockers had nice huge radii! The one set of edges (besides the rear) that ought to be sharp, weren't. Go figure.
And then there is all the **** glommed on to them: ladders, awnings, roof mount a/c units, multiple a/c units, racks, antennae... you name it, it's hangin' out there.