A stroll down Main Street in Picton, Ontario, on a summer day is reminiscent of small-town U.S.A. romanticized in movies about the 1950s. Sidewalks are lined with mom-and-pop shops, while families with toddlers and strollers savor ice cream fromSlickers County Ice Cream – though the artisanal flavors like Campfire Cream and Rhubarb Ginger are distinctly modern. But upon closer look, the small town that sits on Lake Ontario’s north shore, about 99 miles east of Toronto, feels more like the...