Hours: Visitor center open Mon.-Sat. 7-7, Sun. 7-5. Guided visitor center tours are given Mon.-Fri. at 11 and 1, Sat.-Sun. at 10 and 11, June-Aug.; Sat.-Sun. at 10 and 11, rest of year. Make-your-own-ice cream activity is added to the Mon.-Fri. 11 a.m. tour, early June-late Aug. Closed major holidays.