I've done a fair bit of searching, on this site and others, for a simple list of what needs to be done to star a brewery in Maine. I seem to come across one-offs and partial info quite a bit, but I have to imagine there's a comprehensive yet simplest of what is needed in terms licensing. For instance, if I want to start a small brewery and sell tastes and growlers, what needs to happen? I know a liquor license is needed. Is a retail license needed, too? What sort of inspections are needed, etc. I know this sounds like a lot but I have to assume there's a link out there somewhere that I just can't find...
Call the state liquor commission and the town health department. Their job is to give you the requirements, you shouldn't trust anything you read on a message board.
There is an event coming up in Portland just for you. Second or third year. You'll have to look it up, but it's a weekend conference for all people in the beer biz, on every level - brewing, equipment, licensing, insurance, regs, etc. Several presentations by different people in the biz. Is being put on by the Maine Brewers Guild, whom you should contact for more info. Was a big success last year I heard from industry peeps. Great opportunity to gauge whether you really want/are able to dive in. With 70 Maine breweries already in the state, I'd do your research!
Make rhat 93 breweries in ME, and legacy brewer Geary's was just sold, according to the article in the Portland Herald I'm reading right now.