We went to Block last year after our night of runing down the Delaware Bay to Cape May. The way to Block depends on what you want to do and of course your crew. WWilson has given you good advice about traveling the outside route which we have done. I would figure on 30-35 hours. We chose last year to enjoy stopovers in some of the towns along the LI Sound, lots of which are neat. We went from Cape May to Barnegat Inlet (72 miles or so), Barneget to Atlantic High;ands (52 mi), up the East River ( go with the incomming through Hell Gate) to Northport (48 mi) a place we will go back to over and over again, Branford (30 miles), Westport (30miles), Mystic (30 miles) then Block Island (25 miles). Nice day trips...moored or anchored up by 3 and ashore for a tour and dinner every night (some nights we did eat on the boat). Southbound we hit Essex, Port Jefferson, Manesquan, Atlantic City and then Cape May. Aldo is very expensive by the way when he is comming to your boat, but visit his tratorria in the city for the best Gelatos.
This year we are headed to Marthas Vineyard via Newport, Cuttyhunk...then retirn by Greenport, Essex, Northport, Liberty Landing (by Ellis Island), Atlantic City.
If you want more info feel free to PM me.