You should pick up a decent amount...
I think you'll be surprised on how much you may pick up since the altitude of the aircraft greatly increases your line of sight ability to catch the signals.
You'll catch the International push each night as planes from the NYC area head over seas. I listen too them come up from the NYC area as they navigate to MERIT intersection and then are cleared direct to HFD and beyond. In the afternoon you'll most likely pick up a decent amount of return International traffic as well. Traffic to/from Boston bisects the area but again, how much you pick up will depend on your antenna set-up.
I haven't done any ACARS decoding in a few months but as someone else previously said, chances are, you'll only get the airborne side of things. I don't think I ever received any of the uplink messages from my location here on the shoreline which I was surprised about since I get the ground side from a number of ATC facilities both in CT and on Long Island. I thought that if the ground side of ATC came in clear, the uplink side would have too since those uplink transmitters typically reside at or near ATC facilities as well.
Anyway, that's my two cents. Give it a whirl and let us know how it goes.
Best,
MikeMike