Hours: Visitor center Mon.-Sat. 9-9, Memorial Day-Labor Day; 9-7, mid-Mar. through day before Memorial Day and day after Labor Day to early Nov.; 9-5, rest of year. Forty-minute guided tours are given Mon.-Sat. 9-7, Sun. 12:30-7, Apr.-Oct.; Mon.-Sat. 9-5, Sun. 12:30-5, rest of year. Closed Christmas. Allow 1 hour minimum.