Although I live in Pennsylvania, I live in a highly shaded area with relatively high humidity. I constantly have to treat rock walls and fence posts and rails with bleach in the summer to keep moss from starting to grow.
I keep my guns in a safe in the basement using a goldenrod only. After well over 20 yrs. I have yet to find any rust on my guns. The goldenrod does a fine job. I used to use the dessicants also, but quickly realized what a pain in the butt they are to maintain.
As far as drying things out too much, I really don't think you have anything to worry about. I would think it would take a much more arid climate to promote that problem.