As i have the same problem and the same damp climate (Victoria B.C.) i
can say (and have done all listed):

If you can, park in dry garage
yes, take out upper bunk mattresses
use some sort of chemical air drier (ie "Dri-Z-air"), only if parked,
its CaCl2 I think.
place a small muffin fan up in the mattress vacated upper bunk, to blow
air around
make a light bulb based drier, same as boat owners use, or maybe buy a
"golden rod" drier, see West Marine etc
light bulb drier and fan on timer, not all the time BTW
pop top any chance you get on sunny dry days

It helps but... its hard to keep the inside bone dry around here.

Alistair

'82 westy, diesel converted to gas in '94
http://www.members.shaw.ca/albell/

On 26-Nov-05, at 3:46 PM, TC wrote:

So I have not had the pop top up in a few mths
best as i can tell it does not leak water but today is sunny so i felt
it would be a good time to air it out..

There are some small mold spots starting to appear from the
point where the upper bunk folds over all the way to the rear of the pop
top.

I assume this must be an air circulation issue,
so what to others in the north wests moist climate
do that park the westy outside over the winter
I drive it maybe once a week at this time of year.

-remove the upper mattress to allow some air circulation
-treat the pop top with some type of anti-mold goop ?? any brands you
use
-cut ventilation holes in the side of the pop top ??
-pop the top any time it looks like sun in the NW, yah sure :)

what other tricks to make sure when spring comes no tell tale black
spots ?