Diamond State Concert Band Rehearsals take place Wednesdays, 7:30 - 9:30 PM.
From I-95, take the Marsh Road Exit. Go E on Marsh and, once you're clear of I-95, go about 1/4-mile and turn left onto Washington Street Extension. The school will be on your left. Go into the second driveway entrance into the school. At this point, you're sort of pointing at the door you'll need to go in.
Almost straight ahead, you should see glass doors that go into the cafeteria. If you stand at those doors, facing the school and then turn left, you'll see a rather non-descript metal door. Go in there and down the stairs. Follow your nose, and you'll come to the band room.