I really like the Atlantic Coast Route. I have ridden portions of it and live about 3 miles from the route in central massachusetts. Might I suggest that you consider riding along the eastern shore down to NYC. You can do ACA to Northbridge, MA then head south on RT122, RT146A, to RT102 in Rhode Island (wide shoulders). THere are some backroads that will take you down to Misquamicut Beach, then head east to Mystic, CT and along the shore to New London. Hope the ferry to Orient, NY (long island) then ride along the southern beaches down to Rockaway Point, NY. From there, you can decide where in NYC you want to go. There is a bridge that takes you into the city if that is your destination.
I rode this route in the reverse direction from Washington, DC to my hometown in Sutton, MA in 2004. It was a great route. I can give you more details and sources for maps if you need them.