COLUMBIA — A real life nugget from the days of the Gold Rush is the Fallon House Theatre that was built in 1850 and continues with its stage productions year-round today.A colorful Doug Brennan, 63, serves as the resident stage manager who first came to Columbia some 40 years ago with one of the directors of a junior college. Brennan is now the central figure in the daily operations of the facility as a horse-drawn stage coach filled with tourists rumbles down the main street. He remembers those early days in 1973 when he and several other college students did nothing but theater for nine weeks in the old Gold Rush town.