Quebec City is beautiful. We had one full day and a piece of the embarkation day there. The view from the ship, looking up the hill to the Frontenac Hotel is spectacular anytime but particularly at night. We took the Historic and Modern tour and it was very informative.
I'd never been to PEI before and it's a beautiful island. This would be a wonderful stop for a child or young adult just reading Anne of Green Gables. There's a cute gift shop where you can dress up as Anne and have your picture taken. Children, women, and MEN were doing this. Some of the cutest "Anne's" had a beard or mustache.
Bar Harbor is such a cute little town and a beautiful one as well. You can see Acadia, the quaint "cottages" of the rich and famous, of stroll the streets full of unique souvenier shops and restaurants.