A ghost (Jimmie Walker), husband-hunting for his widow (Vernee Watson of ABC's "Carter Country''), spots an attractive prospect (Greg Morris); remembered by the crew as a tubby youngster, Gopher's sister (Melissa Sue Anderson) reappears grown, gorgeous and interested in Doc, and a divorced couple (Conrad Bain and Janet Leigh), seeing off their daughter (Jamie Lee Curtis) and her husband (Peter Coffield), is accidentally locked in a stateroom together on the ABC Television Network's "The Love Boat," SATURDAY, NOV. 11 (9:00-10:00 p.m., EST). The well-intentioned ghost, seen and heard only by his widow, experiences jealousy as his mission appears to be succeeding in ''Till Death Do Us Part - Maybe," written by Ben Joelson and Art Baer. In "Chubs," written by Loraine Despres, overprotective Gopher entrusts his kid sister to Doc to stave off the ship's wolves, not realizing how sophisticated she apparently has become. The long-divorced couple meets accidentally aboard ship and has ample time to rediscover each other while trapped in an isolated cabin in "Locked Away," written by Howard Albrecht and Sol Weinstein.