Try the Darthmouth one anyway. There are always people that do not pick up their reservations (cause they are stuck in traffic jams for instance...),so be sure you are there and first in line when the register opens (even if that is at 7 am) so that if they have a 'spare' list you can get your name on top of it. (And if they don't do a list at least they can tell you what you should do to get your hands on any unclaimed reservations)
Good luck...