I am not American but can hear slight differences between Maine and Boston. Urban accents are often different to their hinterland, let alone those with different formative influences.

Maine has multiple distinct accents, though like the parent said, it's not worth making the distinction unless it's for a project like this.

In southern Maine, the accent is moderate and is more of a general northern New England accent. Yahd = yard, that kind of thing.

The iconic Maine accent is the Downeast accent and is still kicking up/down there. It's kind of nasally and has a lilt to it. You have to dig through a morass of influencer content on youtube to find an authentic example of it, but this is a good one: https://www.youtube.com/watch?v=FZDpx1aLovc

But there are a number of different accents throughout Maine. My favorite without a doubt is the accent in way northern Maine, from the Allagash Valley. It's just a pleasant accent. This is a good example: https://soundcloud.com/mpbn/troy-jackson-allagash-logging

Just an update to this. I realize I misspoke and misnamed where that last accent comes from. It's too late for me to edit the original comment, so I'm just going to drop it in here. There's no such thing as the Allagash Valley, only the St. John Valley.