Hi, Todd-
Thanks for the question.
You do have a little bit of a dilemma, but the answer is relatively straight forward. What works best for you? As far as the process for becoming a Mason, you will probably need to join a lodge in Massachusetts. Whether it is in Salem or Boston is up to you. The lodges that meet in both cities will welcome you. Once you have joined, you could then affiliate with a lodge in Maine. Although your attendance at the lodge’s meetings would be limited while you are living in Massachusetts, many lodges have weekend activities (community service, family, and social events, etc.) that would provide you the opportunity to become a part of their lodge.
I suspect that you will not be able to attend an Open House this weekend, since you will be in Maine. Therefore, I encourage you to contact a Brother in Salem or Boston (or, perhaps both) listed on the Lodge Locater on AskaFreemason.org to learn more about their lodge. This may help you ultimately decide which lodge to petition.
-Robert