Carlisle, Mass., farmstead: gas connection to the house; paving work on the lower driveway; fiber-cement exterior siding; home-automation and media-systems technology; a stairway from the garage to the barn's third floor. On “Ask This Old House”: Landscaper Roger Cook helps an Illinois homeowner with a sinking brick patio and painting contractor Jim Clark shows a Massachusetts homeowner how to strip wallpaper. Also: re-creating molding profiles.