Cynthia Hopkins, a performance artist, will present a work-in-progress showing of her newest piece Saturday at 4:30 p.m. at the Watermill Center, where she is currently in residence. Titled “A Living Documentary,” the work combines elements of musical comedy, autobiography, documentary, and fiction to create a portrait of the difficulties of earning a living as a theater artist in the 21st century. The piece will have its world premiere at New York Live Arts on March 5.