I live in Newbury, which is two towns south of Salisbury, with Newburyport in the middle. My wife is a physician who works 25 minutes away at a hospital in New Hampshire.

It's about 40 minutes to the edge of Boston from here, longer depending on where in the city you're going. The commuter rail runs from Newburyport right downtown to North Station for public transit non-driving access. There are two major highways (95 & 495) that make it easy to get anywhere in general.

While the con is that it's farther flung from the city than your other locations, it more than makes up for it in beauty. The beach and marsh environment is gorgeous, as is Newburyport and Ipswich if you go further south. My suggestion is to drive Route 1A from Salisbury to Salem to see the towns along the way. Spend some time in Newburyport.

Also, the quick access to the mountains in NH and Maine in general can't be beat if that's your thing too. It does get touristy in the summer due to the beach, but that can be pretty fun as there's a lot to do for restaurants/bars/entertainment without leaving the general area!

Good luck on your search!