There are five Mex joints within 10-30 miles.

The Mex gets poor reviews, but some of these people may have never been within 1,000 miles of Mexico. It's in Ellsworth, the working class town where Bar Harbor tourists stop to pee, and has been in operation for decades.
Gringos and Pancho are Bar Harbor side-streets, been going good for many years, are probably very fine, though perhaps not what you'd get south of the border. If you come, we'll check them out.
As everywhere, there's a lot of "global cooking", which to me means odd apparently-random unpalatable combinations of foods. Like a 4-star steak, topped with an inch of wicked-good blue cheese from a local farm; either alone would be great, but together was a waste of decent beef and an overdose of good but strong cheese. Some of the "Mexican" found in Google is really "global": Rupununi is a fine joint if you like something different, but any Mex is happenstance. Bassa is probably also an everything-goes fancy food joint.
BTW: I said you can't get good bread in Maine supermarkets, but even quickie-marts stock taco shells. Yes, Old El Paso cardboard, no relation to real Mexican. But must be a lot of people thinking "home-cooked Mexican".
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fresh seafoodYou'd think. But once in a while we've got stuff that clearly walked down to the Boston fish-market and back. The Maine fishery is small and fragmented. Many restaurants don't want lobstermen coming to the back door, they work with suppliers who often as not get seafood where convenient. And when a 1,700 passenger cruise ship docks in Bar Harbor, they can't all have local lobster... the uncommitted catch is not that large.
Lunt's, Trenton Bridge, and Stewman's will presumably have lobster caught the same day in the local bay. Southwest Harbor is where many lobstermen dock and you might get lobster right out of the trap.
And once in a while you find a treat. I was around Philly in the 1960s, and they made soft pretzels-- excellent! It was yeast-raised, hand bent, and served hot from the oven. With a special mustard. Nothing like hard boxed pretzels. And there are "soft" pretzels made cheap in a factory full of chemicals to keep them "soft" for a week, uck. Tonight, Jack's served us 4-star soft pretzels: clearly made in a factory and frozen, but better than any factory-made soft pretzel I ever had, and served with the proper mustard (except in a glass dish with a knife; the right way is from a plastic squeeze-bottle). This almost made up for the trouble they are having with french-fries.