Grounds daily 24 hours. Visitor center and ranch buildings open daily 8:30-4:30, May-Oct.; 9-4:30, rest of year. Buildings closed most major holidays. House tours are offered based on staff availability. Bus tours depart Sat.-Sun. at 11 a.m. and 1 p.m., and Mon.-Fri. at 11 a.m., late Apr.-late Oct. Closed major holidays.