I used to work at Teterboro airport as a CFI. During that time, I did probably 50+ Discovery flights down the hudson and up the east river. It's pretty easy:
You fly on the right side of the Hudson (sorta like driving). Annouce like a CTAF Using "Hudson traffic, Cessna Skyhawk over the Lincoln tunnel at 800, southbound" or something simular. Listen for the air tour helicopters - there's a lot of em. They're pretty good about annoucing.
We flew south along the hudson. Passing governor's island, I'd go out in the bay and call LaGarbage (hehe) tower on 126.05 and request a Class B clearence up the East river and west over central park at 1500'. They'd normally give it to me, very nice people.
Transition over central park and then turn northward on the right side of the Hudson. Fly over the george washington bridge and you're almost home. The alpine tower is a smaller tower on the jersey side of the hudson on the cliffs. Pretty easy to spot. After that you're on your own.
Check if there's a yankees game, that will shut down the corridor near the stadium due to that stupid 3000+ people TFR rule (or whatever it is).
~wheelsup