rhm, I did this tour on my motorcyle. There are a few ferries from Maine to N.S. We took the Cat High Speed Ferry to N.S, and there are other cruise ship type ferries, that take a loooong time to get there. The Cat runs from either Bar Harbor or Portland Maine to Yarmouth, N.S. On the way out, we rode out of N.S. back to Maine via New Brunswick.
If you all are going to N.S., I suggest you get their free visitors guide Doers and Dreamers:
http://www.destination-ns.com/forms/guide.asp At this web site you can also get a Scenic Trailways map. I am not familiar withit, but it sounds like it could be a useful resource.
Another suggestion I can make is to do the trip in a counter clockwise direction. This is especially true if you're doing the CabotTrail.
It's beautiful in N.S., you all have fun!!