East River - Planning Your Passage for a Fair Current or Slack Water
As JimsCal says the East River is not that bad if you time it right, and your engine is reliable!
You can cut between the Brother Islands, there are channel markers. Keep to the right of Roosevelt Island. When you get near the Hudson river and the Battery and Brooklyn Bridge you can take Buttermilk channel ( behind Governor's Island ) ( a left turn after the Brooklyn Bridge). Unless you desire a closeup of the Statue of Liberty. Buttermilk Channel will exit toward the Bay Ridge Flats, there's plenty of water in there and it keeps you out of the main channel. It's an anchorage area for barges etc. The big boats and Ferries use Buttermilk too so keep an eye out for traffic. I try to stay to port as I approach lower Manhattan to avoid the ferries pulling in and out, but sometimes it's not possible. If you're riding the full current down the east river, you shouldn't see to much commercial traffic coming up, as they usually wait for slack or fair current.
Depending on the wind and current, you may see some chop under the Verrazano Bridge as wind against current can churn it up. just plow through. There's good water to port fairly close to shore.
If you need to wait for a weather window to head offshore you can Hang out in the Atlantic Highlands for a bit. The Yacht Club has moorings with Launch Service for $50. Or you can anchor behind the breakwater and get launch service for $25? I believe. Or you can anchor off Sandy Hook in Horseshoe cove.
The overnight passage to Cape May is Roughly 24 hours. However, you could make it to Atlantic City in a Long day if you leave Dawn or pre-dawn. Otherwise there's Manasquan and Barnegat Inlets, which I wouldn't recommend on your first trip.
If you time the east river for Slack before ebb expect to see commercial traffic doing the same.
Listen to channel 13 and 16
*** Note, Before planning your passage make sure you check the current Local Notice to Mariners to make sure there are no closures or restrictions in place! There are often, races, events, U.N activities, construction, etc. that you'll want to be mindful of.
I wouldn't shy away from the East River and go out around Montauk, The prevailing winds are SW ( on the nose) and there's no good places to duck into. So timing that trip would be critical too. Waiting for a something with a northerly component.
Good Luck! I listened to all the horror stories...at the end of the day.. it ain't so bad, it's very cool.