Portland is the best of the bunch - great food and drinks and a nice downtown. However, Portsmouth NH is closer to Boston with a similar but smaller setting; you'd take the MBTA commuter rail to Newburyport MA or the Downeaster/Amtrak to Dover NH then a taxi/Uber (not sure how much that would cost). Both trains leave from North Station under the TDGarden. Portsmouth - you can walk over a bridge to Maine, so that's fun. Good breweries in either spot if that's your thing. Portland - only downside to me is that the ride can be long for a day trip and the Downeaster is prone to random delays that can be significant and cut into your visit. The station is also outside the Old Port neighborhood, which I think would require a taxi/Uber to access (depending on fitness and and the amount of time you want to kill).

Providence is nice in spots. Federal Hill is great for Italian food. Thayer St area around Brown is good for food. Downtown can be a bit dull.

Salem would be nice now that it's post Halloween. Good walking city and decent food/drink options, with all the supernatural touristy stuff easier to visit at this point. Nothing remarkable about Plymouth in my view.

Provincetown is fun and you'd get a nice ferry ride; hope for good weather of course. Good food and nice walks. There's a stone jetty at the far end of town that is fun to walk, with a desolate beach and lighthouse at the end point of the cape, surrounded by dunes. Just don't get stuck on the jetty at high tide...
​