MHT is great - Reasonable fares thanks to SWA. Easy in/out.

Maine starts north of Ellsworth (or even Machias, Seat of Washington County - the other Maine). Take 95 to Bangor, Alt 1 over to Ellsworth, then Rte 1 to Whiting and 189 over to Lubec. Across the Bridge is FDR's Beloved Island. Enjoy a Sunrise at Campobello. (NB, CAN) Then shoot up to Calais and if you've had enough of the coast and feel the need to see some really rural territory, head to Millinocket or Baxter SP.