A high-speed ferry runs from Bar Harbor and Portland, Maine to Yarmouth, Nova Scotia. Yarmouth is just over an hour's drive from Shelburne. As you look at the ferry schedule, keep in mind that we're planning to have a dinner on Friday night around 6:00 or so.
A number of airlines fly into Halifax, including several nonstop flights from Boston (Delta, Air Canada, United), Newark (Continental) and JFK (American). If you have a connecting flight, it's better to connect in the US to avoid having to go through customs between flights. Flights in the summertime run about $350-450.
The easiest way to get around Nova Scotia is by car. All the major companies have car rental services at the Halifax airport, in Halifax, and in Yarmouth. Shelburne is about a 2.5 hour drive from the Halifax airport.
A couple of van shuttle services run from the Halifax airport to the south shore. They usually run once a day and take 4-5 hours depending on... whatever. There are a few rest breaks at roadside Tim Horton's. Some useful numbers:
Campbell's Shuttle: 1-800-742-6101 or 902-742-6101 (Reservation only 2:30-4pm)
Cloud Nine Shuttle: 1-888-805-3335 or 902-742-3992 (Reservation only 3pm)
Kiwi Kaboodle's: 1-866-549-4522 or cell 902-449-6703 (Reservation only)