Fog sits on the Kennebec most mornings in Randolph, thick enough to hide the Gardiner side until the sun works through it. Dana Lawrence Tree Service LLC keeps lawns along that riverbank — narrow lots, dooryards that tilt toward the water, grass that grows heavy in the damp air. Mowing ground like this is more walking than riding, and the trimming around ledge, posts and old stone takes as long as the cutting does. Done right, a sloping river yard looks level from the road, which is a small trick worth taking pride in. Randolph is a compact place, and a tidy lawn shows the length of the street.