Hours: Center daily 9-6, June 1-Sept. 15; Wed.-Sun. 10-5, in May and Sept. 16-Sept. 30; Mon.-Fri. 10-5 by appointment only, rest of year. Tour departures require a minimum of three people. Tours are given daily at 9 and 1, Memorial Day weekend-Sept. 15; otherwise varies. Closed July 4. Phone ahead to confirm schedule.