Running a twisty seven miles south from US-4 and Bridgewater, Route 100A passes through beautiful scenery and Plymouth Notch, birthplace of Calvin Coolidge, the only U.S. president born on July 4. The small hilltop clutch of buildings is so little changed by modern times, it’s a wonder there aren’t horses with carriages parked behind the visitors center instead of Subarus. One of the most evocative and simply beautiful historic sites in New England, the Calvin Coolidge Homestead District (802/672-3773, daily in summer, $9 adults) has been restored to its 1923 appearance, the year Colonel John Coolidge administered the oath of office to his vacationing son, the vice president, after President Harding died unexpectedly in San Francisco. The house, the general store, and the cheese factory are 3 of the 10 buildings open to the public. There’s also a mile-long nature trail offering fine views of Plymouth Notch and its Green Mountain surroundings.