"Magnum, P.I" fans should circle May 1 on the calendar. That's the date that CBS plans to broadcast the final original episode of the 8-year-old detective series, which stars Tom Selleck. The two-hour program will feature appearances by 16 actors in roles they had played earlier in the show's run, including Gwen Verdon, Howard Duff, Hal Williams, Joe Santos and Shavar Ross.
Former "Hill Street Blues" star Ed Marinaro plays the leading role in "Sharing Richard," a TV movie that CBS will televise April 26. According to the network, the film "explores a timely phenomenon: the shortage of single men for women over 30." Marinaro is cast as a recently divorced doctor who is dating three women, who, unbeknownst to him, are friends. They are portrayed by Nancy Frangione, Eileen Davidson and Hillary Bailey Smith.
The collaboration between England's BBC and New York's WNET-TV that produced "The Miser" on PBS recently will return May 6 with another stage play produced for TV, "Once in a Lifetime," by George S. Kaufman and Moss Hart. Zoe Wanamaker, Kristoffer Tabori and Niall Buggy play the three vaudeville performers who set out for Hollywood in the early days of sound films.
People: Vince Edwards, the former star of "Ben Casey," plays a mobster in the April 29 episode of "The Highwayman" on NBC. . . . Denholm Elliott stars in the May 7 installment of "The Ray Bradbury Theater" on USA Network, with Alan Bates scheduled to appear in the May 28 episode.