It has been 40 years since the first Union Pacific steamer, dragging Pullmans full of wealthy ski bunnies, plowed through the snowdrifts in Idaho's Sawtooth Mountains to open up Sun Valley. Today, it ranks as the country's most elegant ski spa, a chic snowpile for the parkaed and goggled rich.

During the fortnight around Christmas—known to hungering locals as "The Big Week"—celebrities from the East and West Coasts land (often in private Learjets) at a tiny, nearby airstrip. This Christmas the Kennedys, including Ted and Jackie Onassis, flew in. So did Dr. Lee Salk and his two children, and Margaux Hemingway, who grew up nearby, and her husband, Errol Wetson. Another arrival was Paul Anka, who recently opened a restaurant on the resort's quaint shopping mall.

One contemporary intrusion was a bus drivers' strike. Senator Kennedy was so intimidated by it that he took to cross-country skiing rather than cross picket lines around the lifts. After an unsuccessful attempt to help settle the strike, he and the clan headed for Utah's Snowbird resort where, he said, "We can get in some serious skiing."