Opening a museum has an irresistible allure. Then comes the public. 

When Steve Oliver and his wife, Nancy, commissioned the first of many monumental artworks to grace the landscape of their 100-acre sheep ranch in Sonoma County, Calif., they did not foresee a future where they would admit a bus full of visitors a day, three days a week, to tour the grounds in the spring and fall. “It was never my intent,” Oliver says. “It started rather innocently. Now I think we’re booked on every Satu…