I've visited overnight in almost every harbor in Long Island Sound (most many times). In most small harbors, the deeper areas are filled by moorings. Last summer transient moorings ran $45 typical to $55. Most moorings are offered by private clubs, and commercial facilities mostly have only transient docks. I have heard some places are higher but haven't seen it. Inside the Gardiner's Bay area Greenport and Sag Harbor offer town moorings and you pay the harbor master (similar to BI). In North Cove in Saybrook you can pick up free moorings if they have a ribbon attached indicating the owner is away. In the larger harbors such as Lloyd Harbor/Northport/Centerport, Oyster Bay, Manhasset, Hempstead, Greenwich Islands, Norwalk Islands, Thimble Islands, Duck Island Rodes (Westbrook), New London, Mystic, Stonington, Watch Hill, Stamford, City Island, Outside Milford (behind the island whose names escapes me now), Port Jefferson, New Haven, Three-mile, Orient, Coecles, Montauk, West Harbor you can always find room to anchor, although you will have a long dinghy ride to a dock unless your draft is shallow. If you draw 5 feet or less you can anchor in Branford. You can anchor in Mattituck even though it's small, because it's classified as a federal harbor of refuge (it can get crowded though we have always found room) and most people don't seem to realize you can anchor outside the markers if you keep an anchor light on.