In that case, then you want to take Mas Ayoob's course listed above. I took the class back when he called it LFI-1, and was teaching out of NH. No one covers the material in as much depth as he does, and he's the only trainer that I know of who has testified as an expert witness in self defense cases. Ayoob won't teach you the details of self defense law in your state, but he will teach the basics of self defense law in general, and the practicalities of what to do (and not do) before, during, and after a deadly force incident. Ayoob is very entertaining and profane (if that bothers you).
I've taken courses at shooting academies where I preferred some of their shooting techniques over Ayoob's, but none of them addressed the legal issues in as much depth as he does. Ayoob teaches a decent grounding in defensive shooting, but I think Randy Cain is bit better.
I applaud you for searching out this type of training prior to carrying. I did the same.
I don't always agree with everything Ayoob has said or written, but in general I think he makes a lot of sense.
You are correct that he is not in MA, so you would have to travel. Traveling to Florida for a few days in mid-winter might not be a bad thing
A closer (taught in MA) and cheaper alternative would be a course given by AWARE:
http://aware.org/courses/rulf.shtml
Most of the instructors at AWARE have taken Ayoob's old LFI-1 and LFI-2 classes, but none of them have his courtroom experience as an expert witness.