SAN MARINO. A day at the Huntington is a treat, even for kids. Among its many attractions, botanical gardens are the major draw, and they include more than 150 acres of lawns and themed gardens, not to mention more than 15,000 kinds of plants. The original residence, then, houses a wonderful art collection whose specialty is British, French, and American works of the 18th and 19th centuries. The prestigious library boasts incredibly rare manuscripts and books, including a Gutenberg Bible. The Rose Garden Tea Room invites guests to enjoy a traditional afternoon tea buffet, and a cafe with patio seating is available. Special programs and classes, many of them family-oriented, are offered weekly.