We've taken the Scotia Prince ferry to and from Yarmouth and then driven around Nova Scotia...a fantastic place. For example, Yarmouth to Halifax is about 200 miles by expressway or about 2000 if you explore the Lighthouse Trail along the coast. It's a totally awesome look at history, a chance to explore small fishing villages, gorgeous scenery. Northeast out of Halifax you'll come upon the Cabot Trail...more awesome scenery.
Come back along the northern shore to experience some of the wildest tides you'll ever see...about 40 ft in the Bay of Fundy. During tthe summer, there's great whale watching off the northern coast.
Now about the Scotia Prince. For a ferry, it's really not bad at all. It's got a buffet-type dining room, a bar and lounge with shows day and night, and a casino. Rooms are like closets but what the heck...the bunks are sleepable.
So it's not the QE2. But it's more than OK as a ferry ride.
I've never been so sicksick in my life as on the Scotia Prince. I know people who refuse to ever get on another ship again after a night on that thing. If you are not the strongest and most seasoned cruiser...DON'T do it.