NYC NUDE BEACH
From the GS Parkway, take exit 117 for State Route 35/36; you take 36 (it begins there, so there's only one way. Almost right away, you'll start seeing signs for Gateway National Recreation Area; it's 14 miles down SR 36. Gateway National Recreation Area is what you want. Just stay on 36 until, within sight of the ocean, you cross a bridge over the Shrewsbury River. Look for the signs for Gateway; it's to your left, but it's a right exit.
This is the part of Gateway that is called Sandy Hook. (Other parts are at Jamaica Bay, and on Staten Island.) Drive in. In season, you pay a parking fee per vehicle (not sure what that's up to now). They you drive in 4 1/2 miles; just after the Ranger Station, watch for a sign directing you to the right for beach parking; take that right.
After the right turn, the next beach access you come to is Area G, Gunnison Beach. Drive straight on a bit for parking; if Gunnison Beach parking is full (it's fairly common on a good summer weekend), you'll be directed right to more parking, It's a bit more of a hike, then, to where you can get naked.
Seastreak Ferries also offers service from Wall St. to sandy Hook a
couple times each day. They then provide bus service from the
dock at Sandy Hook to the various beaches, including Gunnison.
https://seastreak.com/ferry-routes-and-schedules/between-new-york-city-sandy-hook-beach-nj/