While I am all for a 15 minute drive to the boat versus a 40 minute drive, I think that one needs to look at all the full equation of time from leaving one's house to full sailing to see in this case, the drive time is not the factor.
Time-To-Sail = Time you leave your house door to the time you actually have sails up and are sailing.
For Newburyport: 15 minute drive (for Hazmat17) + 20 minutes boat prep (dock) + 30 to 40 minutes to Open Water if he is on the east side of a draw bridge. If he is on the west side of the bridge, it may add another 30 minutes to allow the bridge to open. So best case is an hour or so before he can actually sail provided that the tides and current are favorable. It could be a as long as an 90 minutes if he needs to go under the drawbridge or even longer if the tide and current are not in alignment.
For Salem/Beverly: 40 minute drive + 10 minute launch ride (mooring) + 15 minutes boat prep (no fenders or dock lines to stow) + 5 minute motor to end of harbor. No need to worry about tide or river current. Take away 5 minutes if you manage to get a slip Hawthorne Cove (Salem). So estimate time-to-sail is about an hour.
So even though the drive is longer, the time-to-sail is on average going to be shorter AND the current /tide/river mess won't come into play, nor will that narrow drawbridge.
Don't get me wrong. Newburyport is a beautiful harbor town. If I had a powerboat and lived nearby, I'd love it.
I am only suggesting to Hazmat17 that Newburyport is not an ideal spot if he wants to keep his soon-to-be sailboat AND go sail it on a weekly basis. If it is only a half dozen or so times, then it may make sense, but his OP says he wants to use it frequently.
Are you a Doctor or an engineer???
(I'm an engineer) I like your Time to Sailing metric - perfectly logical. I've since spoken to a couple local sailors - One neighbor who used to keep his boat in Salisbury (East of Bridge) and said never again - now commutes to Rockport (where he has a summer cottage as well). Also spoke with a gentleman who does private sailing lessons out of American Yacht Club (Newburyport, East of bridge). My wife has been out sailing with him a couple of times with some ladies from the Newburyport Mother's club who wanted to learn. He said most of his fellow club members don't bother to raise the sails until they are out in the bay (30 - 40 min) and getting back in at the wrong time can be a challenge.
Soooo, armed with that information, we are going to explore, Beverly / Salem / Marblehead as well as Gloucester options.
Oh and thanks to all the posters with the Boat recommendations.