Infinite is the variety of woman's place in summertime. Judy Moll, a 10-year-old water baby from Toronto, has been taking water ski championships away from her seniors, some almost twice her age, all summer long. Mrs. Vernon Rudolph of Winston-Salem, mother of five, mid-80s golfer, trapshooter and international fisher-woman, became the first woman this summer to take a marlin off the southeast coast. Mrs. Rudolph fought her fish for more than an hour, had to shoot 15 sharks who gobbled up an additional 75 pounds from her 325-pound marlin. "It was," says Mrs. Rudolph, "a wonderful break in the domestic routine." Mrs. Mary Sylvander, who took up mountaineering at 40, spends her weekends braced against the cliffs of New York's Shawangunks. It all adds up to summer's classic taunt, "Having wonderful time, wish you were here."