When I first arrived in the town of Cavendish, I was a bit aghast as it definitely caters to the hordes of families with young children who are there to see Green Gables. Once off the short strip, however, the National Park is wonderful with unique sandstone cliffs, long stretches of sand, cycling and walking trails, and friendly people. This was my first stop where nearly 1/3rd of the tourists were from the US of A, and I could feel the change of pace.
My initial reaction to Charlottetown was also a bit negative. As I drove into town, there was too much retail, but as you get into the waterfront and historic districts, it's charming. Canada was "conceived" here when the Fathers of Confederation met at Province House National Historic Site in 1864 to plot out the creation of Canada.
I must also mention The Confederation Trail --- a 435 km rolled stone cycling and walking trail that is PEI's portion of the Trans Canada Trail. I would love to ride across the entire island on this route someday!