Salem Harbor, MA
Unless there are extreme temps in the winter for multiple days, ice is not an issue. The incoming/outcoming tides keep the harbor free.
In the winter, there are no water taxi services during the winter. Last Water Taxi services stop Nov 1 and don't start until April 30.
There is free public parking (overnight), first come, first serve in Marblehead (Village St), but not during the winter. They also pull the docks in the winter, so even if you do have a dingy, access is tough.
I don't know about the Salem side, parking wise, but I am thinking no, since Salem doesn't have many egress points unless you go through Hawthorne Cove or Pickering Wharf marinas and they are private/members only.
The harbor is "crowded", but it is also one of the larger ones in New England. It is nowhere near as tightly packed as Marblehead harbor or Rockport for example.
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