I went up there on Saturday. Great time of year to be there too - the waterfall is in full glory, and the wildflowers are just starting to come out. I didn't even know there was an observatory there too. On the drive up you pass by some more rural smaller wineries with a lot more character than the ones along the main drag in Napa, or even along Silverado.
Yesterday I finally got in about 18 miles in the Marin Headlands. Felt good to get in some real mileage and terrain. Lot of people on trails. Many trails were effectively rivers giving back a lot of the runoff from our recent rain. Lots of crows involved in their upside-down-flying courtship ritual but no mammals except for some bun-buns on the way back.