JET-AGE presidential candidates think nothing of dropping in on five different states in a single day. Reporters trying to keep up with them can get lost in a tangle of datelines. "Did he say that in Reno or Redwood City? Did he really make a speech in Manhattan, Kansas?" Files often get delayed in small-town telegraph offices.

All of which meant late nights at the office for Associate Editor Laurence Barrett as he grappled with the task of writing a cover story on fast-moving Bobby Kennedy. Barrett knew just what the reporters were up against. He began writing about Bobby back in 1964 as a reporter for the New York Herald Tribune. Among his more harrowing memories is an interview he conducted in a speeding car. Senator Kennedy was driving with one casual hand while the other banged his knee for emphasis. Barrett, his eyes searching for disaster on the road ahead, had an understandably difficult time taking notes.

In recent weeks, Washington Correspondent Hays Gorey found traveling with Kennedy not a bit more relaxing. One night just before the Indiana primary, Gorey was entering his motel, worn out and ready for bed. "Had your dinner yet?" asked a voice with a now-familiar accent. "At 1 a.m.?" said Gorey. "Of course." Said Kennedy: "Join me anyway." Gorey did. When he crawled out of bed early next morning, the first person he saw was Bobby, briskly walking his dog Freckles. That exercise was cut short when the tireless candidate joined a game of touch football. "Sometimes," says Gorey wistfully, "he goes to bed early like other mortals."

Washington Correspondent Lansing Lamont, who joined the Kennedy caravan last week, also found it hectic. But he had his share of anecdotes from previous travels with Hubert Humphrey. "One afternoon in a jet over Nebraska, I suffered a strange chest seizure after eating a hamburger," he remembers. "I was in agony all through an interview with the Vice President." Ex-pharmacist Humphrey rushed to his medicine chest in the tail of the plane and produced a pill. "Take this," he said. "It will relax the spasm in your esophageal tract." It did. Later, Lamont's doctor confirmed the Humphrey diagnosis.

Now and then, our campaign reporters do find moments of relaxation. Washington Correspondent Bonnie Angelo, for example, found it a distinct pleasure to stand by idly while Vice President Humphrey jogged for exercise during an airport delay. The scene was a welcome contrast to her regular beat. "When covering Lady Bird," she says, "reporters are expected to join in the jogging."

Pop Artist Roy Lichtenstein, who painted this week's cover, says that Kennedy is one of the very few real people he has ever portrayed. The 44-year-old artist usually turns out comic-strip-style superheroes with square jaws and their girl friends with superperfect coiffures. What he liked most about Kennedy, he says, was his "lively, upstart quality and pop-heroic proportions as part of a legend."

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