I don't know how far away you are, but there always used to be VERY GOOD crabbing down towards Alpine (NJ) which is just a little south of the Tappan Zee bridge. Another spot that is good is the area surrounding the Tappan Zee, specifically Piermont. If you're not familiar, Piermont is actually the town directly south of the Tappan Zee, on the West side of the river. If you come south of the Bridge, You'll see a small pier at the end of a road coming out into the water. Excellent crabbing and fishing off the end. If you follow the south side of the road into the shore, the river (stream, creek, whatever it is) is very "marshy" with grass and stuff. I always wanted to put my small boat in there and try it out. Now that I moved down here to FL, I guess I'll probably never get to try it.
Anyway....I know for a fact that anywhere South if the Tappan Zee should be very good for crabs. I would suspect that even up your way you can do pretty good, but I don't have any experience that far north.
I hope this helps you.