hey- i rode through pei earlier this summer during my maritimes tour. i rode from the bridge up through summerside to north shore then down through charlottetown towards the ferry. i found the roads to be low traffic (except for dump trucks) , even on " highways" and they were smooth with a shoulder for the most part. i was going to spend an additional day there but there was CRAZY winds that wouldn't stop. apart from the riding, i just couldn't hear anything. so i just headed toward nova scotia instead. hope it's not windy for you.
-joe