The trail goes between the southern end of Willow Lake and a NYCMTA Subway Yard. This is at the southern end of Flushing Meadows Corona Park.
The Trail was accessed from Grand Central Parkway Service Road at 72nd Road, though Google has the "Pat Dolan Trail, Willow Lake Preserve" labeled at the other, east, entrance, which is at Park Drive East near 73rd Terrace. It looks pretty clean from Google Earth on the east side of Willow Lake. The footbridge crosses what seems to be a gazillion lanes of Grand Central Parkway traffic and boy it sure is noisy. I expect that the east entrance is similar as it crosses the Van Wyck Expressway by similar footbridge.
Bring your boots as the trail is mucky (see photos) but remarkable in that it is fairly pristine, despite the road roar of the Grand Central Parkway.