Cuttyhunk may be a tad lonely in March, with not much in the way of supplies or other warm things you may be looking for should you get there. Mainland stopovers might be better advised. Bring ALL your ski gear (including goggles) AND waterproof gloves. The trip will be colder than you believe possible. Is there a cabin heater on board? From the CT river in a boat your size & speed, you may want to check out Stonington CT if the weather is nasty at the outset. Point Judith isn't much further along either, but as a fishing port, is likely to have marinas open there too. A bit further along is Wickford, which offers more protection without having to get as far off -track as going all the way into Newport. If the timing/distances work out well, Padanaram (So. Dartmouth, MA) is a good spot, along with Mattapoisett. Onsett is up right by the entrance to the Canal, but apparently offers little other than holding ground - I haven't been there. Use the guides suggested in other posts (Embassy, etc.) to verify that places will be open and what services they offer when you plan to be there. Some may not be operating on a 9-5 basis that early in the season, and may not have launches in the water yet.