Resorts successfully melding turn-of-the-last-century opulence and contemporary impulses for fitness and healthy living are rare, so for those with the discretionary income or others who'd like to splurge just once, this is the place. A guard turns away the unconfirmed at the gate, so there's no popping in for a look around. The core facility is an 1897 mansion modeled after Le Petit Trianon at Versailles. A fire in 1949 left only the magnificent library untouched, but that loss has been offset by major renovations. Sweat away the pounds in the huge spa complex, with more than 50 fitness classes and related activities a day, weights, an indoor track, racquetball, squash, and all the equipment you might want. Skiing, snowshoeing, kayaking, canoeing and hiking are added possibilities. The staff includes physicians, nurses, and psychologists, as well as sports and cooking instructors and massage therapists. Guest rooms are in contemporary New England style, with every hotel convenience except tempting minibars. After you've been steamed, exhausted, pummeled, and cleansed, the next big event is mealtime: "nutritionally balanced gourmet," naturally.