Wow, that is quite a ride!
I would be heading far to the west, if I were trying a ride like that. The ACA Atlantic Coast Route
http://www.adventurecycling.org/rout...anticcoast.cfm
crosses the Hudson at Poughkeepsie and then cuts through Ulster County to head along the western border of New Jersey. A lot nicer riding, I should think, than Putnam and Westchester Counties!