I would suggest getting a copy of the tidal current tables and tidal tables 1 2 and 3 to plan your trip. If you do not know how to use them I suggest learning before making the trip. The Tidal range and current velocities increase as you sail towards higher latitudes. Additionally I would recommend downloading The Coast Pilot Nos 2 & 3. Office of Coast Survey - United States Electronic Coast Pilot download
The Coast Pilots will tell you alot about what you need to know. It does help to know how to pilot a vessel. In fact I would not take an extended voyage without having someone on board who knows how to navigate WITHOUT a GPS.