RE: Prince Edward Island Potatoes
We mostly go up in Summer, so don't know too much about Spring. Up until about mid-July, mosquitos can be a distraction, then from mid- to late-July is peak tourist season. The latter half of August is about best -- you can get new potatoes and most of the oturists are gone. September is also good, though many of the rural restaurants and tourist attractions are closed. Best time to take solitary walks along the sea.
Therre are some other forums at this site on food in PEI and Nova Scotia, when you get to trip planning.