Here are partisan swing and trend maps for Maine 2012 Presidential to 2014 Gubernatorial. (Cutler obtained between 7 and 10% in every county, so that introduces a minor variation).
The smallest swings toward the GOP in Maine were in the North/East parts of Michaud's district (and also in in Portland), but the greatest swings toward the GOP were also in Michaud's district - in the West.
On the one hand, Androscoggin County swung hard to LePage compared to the Presidential result. On the other hand, Aroostook County was the smallest swing of any county. So I'd question whether French-Canadian identity and/or social conservatism is very explanatory of this result.