Good luck with your planning and your trip.We are planning to sail offshore from Florida to Maine in 2014.
Is the hurricane risk too great if we can not leave before July 1st? [No. Even though the official hurricane season opens 1 July (or did they change it to 1 Jun?) hurricanes frequency in July and especially early July is low.
Where do we find routing information? I don't know this guy and haven't used him and have no interest in pushing him business but his website is detailed and he may be able to help you. Offshore Weather Routing, Atlantic & Pacific