I've been reloading in an outdoor building for many years.The only things that will form surface rust on them are the outer surface of your dies,or anything else that is touched by your bare hands.
A little surface rust on the outside of your dies doesn't hurt a thing.You can take it off with some tranny fluid and steel wool,if it bothers you.
My primers are on a shelf -never had any problems,and I have close to 90lbs of powder on some other shelves-no problems.
As long as everything has lids,and is boxed up,it'll stay just fine.
This is about as rusty as the dies will get,if you use them a lot like I do.