I interviewed for the Maine track already and I commuted into Boston from a suburb in undergrad so I can give a little insight for some of your questions!
1. I can almost certainly say no, commuting into and out of Boston wouldn’t be ideal during M1. I commuted 1-2 hours (Boston traffic and MBTA system SUCK) just during undergrad and found it to be a huge drain on my time and energy.
2. The student panel during the interview explained that for anyone wanting to do the LIC, placement is by lottery. You rank your top few choices and then they place you. I think they said that almost everyone gets their first or second choice usually. I was interested to find out that there are more students than LIC spots, so, theoretically some people who want an LIC could not get one at all of a lot of people sign up for it. (If you don’t do LIC you stay in Portland and do traditional block rotations at Maine Med).
3. Yes, everyone lives in/very near Portland for M2. People who do block rotations stay. People who get LICs move to close to their clinical site (school helps with this) for M3-4. There’s still ~once per month that people on LICs have to come back to Maine Med for one thing or another so you do still see your classmates relatively often in the academic setting. It’s up to you how often you guys work together to see each other in a social setting, but it sounded like it’s doable for the current students.