March weather is a wildcard. We've had mild winters the last few years with little snow, but parts of central Massachusetts received 18" yesterday. I'm in Boston and we had about 4" of snow. It's the first time in nearly two years that I've had to take out my shovel. So, plan for the worst and hope for the best. Note that if you're in one of the larger cities on St. Patrick's Day, it can be either fun or annoying (and expensive either way).

I agree with the advice above to skip the Cape in the off-season. Newport will provide many of the same sights but with better food and more activities.

Portland is a foodie haven. Highly recommend.

Hiking can again be dicey due to changing weather. You might consider the Woodstock Inn in Vermont for a mix of the picturesque, food and some less challenging winter hikes. Stowe has some nice multi use trails - and the Prohibition Pig in Waterbury nearby is a craft beer mecca.

I'd counter the advice on New Haven - great pizza and Yale is nice but that's it. You'll get an Ivy League campus experience if you visit Harvard while in Boston (or Brown in Providence, a good stop for an afternoon).

If you do want to stay in the Berkshires, try Williamstown or Northampton - college towns are more alive and there are good hotels, food and museums.

Others may have better input on locations I haven't mentioned. Enjoy!