San Francisco has some great public parks! Which are largely closed, but not REALLY closed.
During the health order, we are supposed to stay within walking distance of home. For those of us who used to walk 7 miles a day, that is limiting, but not completely oppressive... though I miss many of my favorite walking spots that are usually a streetcar away. (My streetcar stopped running during the health order.)
There are signs up all around this lake encouraging us to take precautions: to exercise alone, to not play sports that involve sharing a ball, and to keep at least six feet away from others. We did a reasonably good job, I think.