Originally Posted by
Askartus
... our first trip to the New England states in March ...
we would like to stay in Boston for 3 nights, exploring the city and maybe doing some say trips to Salem, Rockport, etc..
...rental car and drive along the coast and the other New England states. We are fond of good food and drinks, hiking, sport, history and anything interesting.
Since I enjoy off season travel myself, I won't discourage you to make this trip. Since I live north of Boston, I will agree with those who mention the weather being an issue. Please come prepared with a FLEXIBLE plan and adjust your activities when you see the exact forecast for your dates. You will enjoy your trip more this way, I think.
You can use the commuter train to access coastal towns north of Boston very easily, but it will be more pleasant on a good weather day. Salem has plenty of indoor stuff (I'm a member of, and enjoy, Peabody Essex Musuem) as well as a coastal location, but pure scenery and light hiking are better further north. If you want to plan a firm schedule and stick to it regardless of weather, I might pick Salem over other local towns. Restaurants and sites will be open year 'round here.
If you will plan after seeing a forecast, Parker River National Wildlife Refuge (6 Plum Island Tpke, Newburyport, MA 01950) is beautiful and popular with bird watchers (if coming by car; also I think March is too early for many seasonal birds), or here's a nice link to some MBTA (transit) accessible walks north of Boston.
https://www.baycircuit.org/
Also check out Massachusetts nature/wildlife sites at:
https://www.massaudubon.org/ (I'm a member of this group, too)
and
https://thetrustees.org/ (my favorite on this site is an art/sculpture museum called deCordova, combining nature with culture.)
If you enjoy history sites combined with the outdoors (and the weather is good), I am a big fan of Old Sturbridge Village in Sturbridge, MA.
https://www.osv.org/ This is a restored town circa 1840 where you walk around and see not just one house, but the overall "ecosystem" of this place at that time; I love seeing homes and business together in context around a town square. For me, it is a bit far as a day trip, but I also take a LO-O-O-ONG time in most museums relative to other people, and certainly I have done this as a day trip from my home. The best event OSV does (for me) is a winter one--Evening of Illumination--so off season doesn't dampen my enthusiasm for this place at all.
Regardless of how you plan to spend your days here, make sure to pack lots of clothing layers to keep comfortable if you get wet/chilly/winter weather, so you can enjoy New England in March. (Autumn is the most beautiful season here, I agree, but there is plenty to see and do in all seasons.)