On a cloudy afternoon in Peterborough, New Hampshire, apron-wearing workers emerged from a green nineteen-fifties lunch car, stood behind a banner that read “The Peterboro Diner Welcomes You to Grover’s Corners,” and said things like “The beautiful people are coming!” and “Geez, Louise!” Two charter buses arrived and out they came: Jim Parsons, Katie Holmes, Ephraim Sykes, Zoey Deutch, Richard Thomas, and two dozen other cast and crew members of the new Broadway revival of Thornton Wilder’s “Our Town,” which begins previews this week. “Welcome, welcome!” the diner’s owner, Melanie Neily, said. The visitors, after a five-hour drive, gamely greeted their hosts and proceeded inside for lunch; they resembled regular tourists, except for the slightly suspicious glamour of Deutch (Emily Webb) and Holmes (Mrs. Webb), who both wore fashionable sunglasses…