West of Fisher's Island, the entrance is not very protected and can be a rough ride in.
We stayed at Thamesport Marina for $7.50/foot/week (860-437-7022). Very friendly staff, most affordable marina in town. However, the dock offers no protection from the channel, and because of the constant boat traffic it's a very rough place to stay. Not an enjoyable place to live aboard.
We ended up being in town for Sail Fest -- show up early if you're going! A fair downtown, live music, and an amazing fireworks show. The harbor gets completely full of boats, mostly powerboats.
The city marina has moorings for $25/night. There's also a free dinghy dock at the city marina.
We spoke with a sailboat that anchored right in front of the city marina all week (getting a good spot for Sail Week), and he said it had good holding. The train goes by frequently, however, and the bridge makes a lot of noise each time it raises and lowers.
The town itself seems to be very much feeling the recession, very run down.
There's a nice co-op located up from down town, Fiddleheads. Nice selection, local produce and eggs, farmer's market during the summer, Tuesdays and Fridays.