Would it be too out of the way to just come down I-91, then across on I-89? At least you'd be on major roads the whole time, unless that's what you DON'T want! ;o) In March, it would be after the major snow season, though being New England, you just never know!
I detest I-89...much druther avoid it if possible.
I think the state route way'd be faster, though it's still close to a three hour drive. I'd probably have to take a half day at work if we wanted to get there with much time to spare.