A friend & I biked on the eastern 2/3 of PEI 2 years ago. We arrived by ferry at Souris (from the Madeleine Islands, a wonderful place to visit, though the cycling is challenging due to strong winds most of the time). We biked part of the way to Charlottetown on the Confederation Trail, and partially on roads. Both were fine, and traffic was light on the roads. We biked along the north coast for a while before heading down to C'town. From C'town, we biked toward Malpeque Bay, mostly on roads. Again, traffic was light and the roads were good. We biked back to C'town through the center of the island. We debated whether to take the trail or roads back to C'town and decided to take roads. We regretted that decision. That particular road was an endless series of big hills (on PEI? Who knew?) and big descents most of the way back to C'town. All of the other roads we biked on were level to gently rolling hills.

The only place where there was a serious amount of traffic was going in and out of C'town, and even that wasn't so bad.