Are there any atheist churches or support groups in Maine?

[Parrill Apple]

You should try Craigslist for your area. I'm not near Maine, so I wouldn't know, but I have noticed there are local discussions for every topic on Craigslist and that includes an Atheist section.
Of course some Atheists can be rather pedantic insisting that their version of Atheism is the only version worth noting etc. but you can find truthers of all religions. While there may not be an Atheist gathering, you may find a truther gathering at a coffee shop or book store, which includes Christian and Neopagan participants as well.
If you can't find one, post on Craigslist to start one!
On facebook there is the Coffee Party which was named in a reactionary way against the Tea Party, but which basically is opposed to the Dem/Rep party.
So search for meetings of the Coffee Party to find similar open minded people who are not brainwashed.
Sadly there will always be moles trying to infiltrate, corrupt, and mislead every group. The most you can hope for is to meet a few people with whom to become friends.

Here's a link to craigslist for your convenience:
https://forums.craigslist.org/?forumID=4&areaID=169

Note, it is to the OPEN forum, not to the Atheist forum, and there are posts from people from all over the world there, but posts from Maine are sorted to the top and begin with "mne".