The McDonalds mansion in Freeport is the classiest place in Maine as others have said.

Personally, I think either the East or West End in Portland would be a nice spot due to all sorts of restaurants and breweries and such not being so far. Or something along the Acadia Park Rd / Cadillac Mtn (just know you need reservations now).

If you want a relatively quiet spot check out Grafton Notch - nice waterfalls and mountains, short hikes with great views, and not too far from Bethel (which isn't huge but has some business)