A visit to the di Rosa Center for Contemporary Art in Napa is a delightful way to spend a morning. It contains experimental works of Northern California artists from the mid-20th century to the early 21st century in an outdoor 200-acre setting and two galleries. Perched on a hillside, an impressive 30-foot-tall fire-engine-red steel sculpture by Mark di Suvero conveniently marks where to turn off Highway 12.