“Mad Men” will return for its sixth season — and what is planned as its second to last — on April 7. That premiere episode will be two hours long, the network said, and written by the “Mad Men” creator Matthew Weiner and directed by Scott Hornbacher, an executive producer. The following week’s installment, written by Mr. Weiner and Matthew Igla, is directed by Jon Hamm, who plays Don Draper on the series.
