Yes, drive through New Brunswick. If you want to do Grand Manan Island or Deer Island you need ferry. There is bridge at Lubec, ME* to Campobello Island. I've visited GM and C islands and used to own land near Lubec. Beautiful country.
Hopewell Rocks, Tidal Boar, Fundy National Park, Acadian Historical Village are some my favourite places, things to do.
NS ***********Louisbourg reconstructed Fortress, staffed in period dress and talk. If you do Cape Breton's Cabot Trail, make sure to go north to Meat Cove. IMHO the Cabot Trail is beaten by Gros Morne National Park at least 10 to 1. But yes, it's a ferry trip and at least 2 weeks to tease yourself. I've lived in 3 of Atlantic Canada's provinces. I like lots of more places in NS too.
If you're going to PEI, take the ferry to and the bridge from. Bridge is cheaper and you only pay when you leave. I can go on of course.
Chances are you'll be coming back
Go to: www.gooogle.ca and search "name of province and tourism" for visitors guides. I prefer calling because then I get the special booklets for hiking or other interests.
Budget: allow for eating out more than once. Lot of good restaurants.
:B
* Campobello border guard once told my father he'd written in the log for the night: "admitted one skunk, no questions asked.