Robert Frost arrived in Vermont 100 years ago and stayed, in various locations, until he died in 1963. He bought an old stone farmhouse in South Shaftsbury just north of Bennington in 1920, and he wrote “Stopping By Woods on a Snowy Evening” there one summer morning in 1922. He had stayed up all night writing another poem, “New Hampshire,” and when he slipped outside as day broke, “Stopping by Woods” came to him, he said, “like an hallucination.” Frost’s presence in Vermont is the subject of a special...