It's not really setup in the database that way (i.e a location hasMany events, but an event only belongs to a single location). I could make it so that you could control click to bulk select locations, but it would then create 3 (or how ever many) database rows for that event: the disadvantage being that when you wanted to edit the details, you'd have to do it for each entry.. plus if you've got say, 14 locations, it would display 14 entries for that day on the calendar.

Plus, I'm looking into creating multiple sites with multiple locations within them, so that might be an added level of complexity..

I second the multiple locations. And I too agree that is gets a little complicated, but starting with one and then having it make multiple entries for each event is acceptable.

I'm interested it your multiple sites, multiple locations...