Ok had a look about for you, do you know the precise area of the entrance? might make searching a bit easier but heres what iv found so far:
Plattsburgh Air Force Base:
Location: New York.
Description: This installation was another base that was put on alert during the 1975 Loring AFB intrusions. UFOs have been sighted at this base
(especially over the base's Weapons Storage Area).
www.geocities.com...
New York City
There is an entrance to the tunnels in New York City "in the vicinity of Midtown Manhattan that can be reached through an abandoned elevator shaft
that only very few know about
www.ufos-aliens.co.uk...
Some info on tunnel network etc
dont know if relevent but:
NEW YORK CITY HUGE RED LIGHT UFO
MANHATTAN -- On June 20, 2000, Helene Gould reports she was driving on BQE when she saw a large red shape flying low over the NYC skyline. It traveled
from lower Manhattan to Queens in two minutes. My friend who was driving saw the red light, but he could not really look since we were driving over
the Williamsburg Bridge in the opposite direction of the craft. It was a very large singular circular red light flying very low and moving very
quickly
ufoinfo.com...
Its hard to find info on the new york entrance not alot going about regarding it.