Can I sign-up at multiple locations?

Yes, you can signup at any/all locations where you think you will originate your travel including for your return trip. Your signup is unique to that location. Once "signed-up", you'll remain on "the list" for THAT location for 60 days or the duration of your leave orders or authorization, or you get manifested on a flight (does not include enroute) at that location whichever occurs first. When you depart a location you will be removed from THAT location's list only; your sign-ups at the other locations are NOT affected by what you do at another location.