The name is from Rio Grande del Sur, as stated by Charlie Baum, but its context is the south of California.
Don't let Catspaw and Rapaire scare you with bad memories of their Henry Miller days there.
The Ventana Wilderness is a great place to hike. Good campgrounds in the region, some that can only be hiked into. On the coast, Point Lobos is a good place to watch whales, seals, etc., and some of the trails along the coast are good.
Don't go at the height of the summer RV season (harumpf! should be banned).