Not sure reading your post where you are headed, but if its the Southwest, I agree with Drew about the UV damage. Along with the UV, things dry out badly in single digit humidity, like rubber seals and such. Then there is the dust that gets on and into everything. So keeping things dusted, washed, covered, etc is important. Mold and moss certainly not an issue.
On the other hand, if you are heading to the Southeast, while it is sunny and hot most of the year (think Florida), UV, leaks(frequent rains), mold and moss are an issue.
Just my 2 cents having spent time in both areas.