I think Maine.gov has a lot of the info you desire.
I'll say this, as a transplant here in Maine, getting to know the neighbors will do you more good than going to the town office for things. Being a good, friendly neighbor will gain you a lot leeway with your "projects". Also unless it's a MAJOR build, most people just don't care what you do. Having a good hedge where people can't see what you're doing is a good idea, just don't be a shut-in. In my
experience Mainers are "live and let live" folks. They tend to keep quietly to themselves but are genuinely nice people and willing to help if you need it. I move here from Rhode Island a few years ago and have been so happy that people here just get along without a lot of Drama.
What made you choose Maine?