Boston practical info

Hi everyone,
My husband and I will be traveling to the USA, Boston during the
months of October and November.
We have been there before but not for more than one week, so we don't
really know all that much about Boston.
We would like to know more about good sea food restaurants, a market
place where we can buy fresh food and vegetables ( we will be staying
in Charlestown).
What musea are a must?
How can we best travel to Salem, Vermont, Maine,...

Thank you

Nikita