North of Route 1 the Stonington countryside opens into hayfields and stone walls and lawns that get measured in acres rather than feet. Maple Lawn Farm keeps that kind of ground: broad mowing that must stay even over a rolling grade, trimming around wall ends and old fruit trees, a defined line where lawn gives way to field so the boundary looks deliberate. April means raking out the winter thatch; late fall means leaf clearing beneath trees that drop enough to bury a driveway. Mulch and bed work fill the middle of the season. Big lawns are unforgiving of a careless pass, which is the whole reason to take the slow one.