While in Charlottetown, you'll be able to get in touch with Canadian history in a way unlike almost any other city. This city, historians will tell you, was the site of a 1864 Conference which saw the birth of this country. It's architecture, streets, museums, and historical heritage are all in evidence everywhere.
While in town, you have to make sure you visit St. Dunstan's Basilica, an imposing and awesome Gothic Revival jewel to rival any in Europe. You can take incredible pictures and see up close a unique Basilica in Canada.
The Confederation Arts Centre is also worth a whole day's visit, with exhibits fit to rival any museum.
You should also take the family to Victoria Park for hiking and a sweet picnic, and get a little more history and architecture at Province House, a preserved manor from the 1800s with guided tours.