Willow Acre is a family's corner of Chestertown's historic district: a white clapboard house with a red door and a gingerbread porch, the weathered carriage house behind it, and more than an acre of lawn, flower beds and a footbridge over the creek beyond the garden gate. Washington College and the Chester River waterfront are a two-block walk. Your hosts live next door, do their own cleaning and answer texts at any hour, and otherwise leave you be.