We spent three weeks on The Rock. Wasn't near enough but time was a factor. Bit sobering when you look at the mile posts on Signal Hill and see that you are 1300 km from London England, or about the same distance from Rome as you are from home and have to drive all the way back before it starts snowing in the mountains. Thought the ferry was reasonable considering, but that was ten years ago.
A few comments
PEI is very nice, Charlottetown is a very pretty little city. The ferry was more expensive than the bridge so we made sure to take the bridge back.
Spend some time in Cape Breton. Cabot Trail, Louisbourg Fortress etc.
Halifax area has lots. There are some decent parks around Peggy's Cove which is nicely placed between Halifax and Lunenburg.
Bay of Fundy National Park in New Brunswick. St. Andrews is a very nice town just north of the Calais border crossing. The Kiwanis have a park right on the water from where you can walk into town.
X2 on Bar Harbour and Acadia National Park. Very nice.
