Hi, my Winne Adventurer 37, 2001, has what sounds like the same fault as you are describing here---if what you mean is that the matt black metal panelling round the storage bins is rusting. Can't see a thing with the doors closed, but rusty where the panels meet and along the lower borders,-- is that it?
I have also seen the same thing on a Winne Ad of about the same age that I looked at before buying this vehicle second hand. My vehicle was not used at the seaside, and certainly not in the far north. (ps in case you are wondering, you don't see RVs on the road in Canada in winter conditions, except to go south, that is.)
This problem initially perturbed me a bit, but really it's just a cosmetic problem. I'm either going to get a body shop to treat it, or do it myself. I called Winnebago about it but they seemed not to have heard of such a problem before. However, I didn't really expect them to address such a problem in a seven year old vehicle, though rusting in a four year old seems rather harsh.
Maybe there is a case for polling Winne owners with a view to pressuring Winnebago to fix this, though perhaps that is a naive idea. They do carry those metal panels in stock or can make them for you, but I'd much rather they put them on and didn't send a bill !!
)
Rankjo