Although Midnight Shores is located on an island, going to the mainland for trade or visits isn't difficult at all! Midnight Shores has various ways to cross the Northumberland Strait and land on Nova Scotia.
Note: As Midnight Shores stretches from coast to coast, there is a small path manned by a Gerard (pNPC) in the Kingsweald forest that loners and outsiders can pass through to get to the other side. Merely have your character howl at the start of that path, and Gerard will soon appear to help him or her cross!
One of the main ways to go to Nova Scotia is by utilizing the ship. The ship is manned by 4 NPCs - Janus Stormfall, Ember Stormfall, Thomas Ryder, and Jerome Gryphon. Every few days, they will take the ship (which is large enough to hold up to 20 Luperci as well as livestock and goods) to the mainland and back.
If you are part of Midnight Shores, no permission is needed to assume your character hitched a ride on the ship -- your character may come and go as he or she pleases, and all that needs to be assumed is that he or she rode on the ship with the NPCs.
If you are NOT part of Midnight Shores, the NPCs of the ship will take passengers across as long as they are polite and demonstrate good manners. If your character is aggressive or secretive, he or she will not be allowed to ride!
Midnight Shores also has a small stock of various canoes and ships, located in the Charlottetown harbor. These are communal - your character may use any of them, provided they are returned at the end of the trip. Keep in mind that these canoes and boats are more suited for small visits; if your character wants to bring livestock, a horse, or many goods, they are better off taking the ship across the Strait.
During the winter, the Northumberland Strait freezes over and becomes ice. This allows Luperci to walk over it as if it were land - be careful, though! Parts of the ice may be more fragile than others; it's safest to cross on the Southeastern edge of the island during this time of year, as that is where the ice is thickest.