Hours: Fifty-minute guided tours are given every half-hour Mon.-Fri. 10-4:30, Sat. 10-6, Sun. 10-5:30, early June-Labor Day; Mon.-Fri. at 11, noon, 2 and 3, Sat.-Sun. on the hour 11-4, mid-May to early June and day after Labor Day-late Nov. (weather and conditions permitting). Other tours are offered; phone for schedule and prices.