The safe is a FANTASTIC idea!! I would have never thought of that, but it is GENIUS!
What I was thinking was anything that can be used up since dorm rooms can be cramped. Scented candles, body wash, toothpaste, tooth brush, shampoo & conditioner, razors, lotion, nail files, hand sanitizer, gum, candy, and a distinctive USB flash drive are some ideas.
If she doesn't already have one, maybe a lightweight blanket or quilt - one that would be good in all seasons - and/or a nice pillow (down?). I always like a good, sturdy (canvas) tote bag. Notepads or nice stationary, a nice pen, some stamps if she sends any letters or bills. Shower shoes, a back scrubber or back scratcher, or a gift card to favorite clothing store, grocery or gas station nearby.
I can't think of anything else. I may update if I do. I am curious to see what everyone else will suggest! :)