The only way you could do this is to temporarily put a display on the computer. Plug the USB drive into it. In MC, add a Media folder (or whatever you want to call it) to the Library and anything you add to the USB stick should auto import into MC.
The good news is that once it's setup, it should troll through the folder and import files automatically.
You can't add a Library search location with Gizmo as best I can make out.