I have done this (21 years ago) and the counsel from Sailingdog is right on. Only we ended up in Oxford, MD with stops in Atlantic City, Cape May and transiting the Chesapeake/Delaware Canal, then down the Bay. Took us three + weeks with lousy weather.
We left SW Harbor April 1 and headed straight for P-Town. Enjoyed a quiet night and then 40-50 knot winds for 2 days in P-Town harbor on a mooring. Quite delighted not to have been on the east shore of the Cape or anywhere south of Monomy Point. Headed south through Cape Cod Bay through the canal to the Refuge at Point Judith and anchored. Awakened to 5" of snow the following morning while the next weather attraction went through. Then south passing west of Block and straight to Atlantic City. There's an awful lot of commerical activity on that part of the transit. Extra care using radar
day and night.
Back to Point Judith, as you then head east, if you enjoy the Race on the sw corner of Fishers Island you'll see many less lobster pots. Instead, through Fishers Island Sound, you'll think you are back noreast. Further east, dodge the high speed ferries as you transit the Sound. And pay close attention to slack tide when you approach NYC. One does not wish, should not, enter that Hell Gate area (very approrpiately named) unless it is slack.
Obviously keeping track of tides through the canal, the Race and Hell Gate, as previously mentioned, will generally make a more enjoyable and less frightening transit. And June will not doubt delete the snow and much of the high winds.
Finally, I'd not go offshore and around the Cape and her Islands, much less Long Island. There are great harbors to enjoy in fine weather, and in challenging weather, you'll be glad you're not offshore. The Atlantic side of Long Island can have substantial fishing and commercial traffic as well as few safe harbors to find protection.
Check into Stonington, Port Jefferson, Huntington in the Sound, Hadley and P-Town for the Cape, and Camden if you don't take the direct SW Harbor to P-Town. I did mine in a 67 B-40 aft cabin yawl, sounds like you'll enjoy the transit in your SW-42 yawl(?). It should be a lovely ride.