We went on a great hike on a fire trail in Marin Co. from Alpine Lake Dam northwest to Kent Lake. We found a great swimming hole with deep pools, but no frogs. It was a hot dry day, so being down in the valley was a plus. Here is a map of the area.
The only incident was that Oyster slipped on a rock in the river and cut his hind leg near the ankle. It was a pretty good gash, but to his credit he only started limping when we were about 200 yds from the car. We also rescued another hiker whose dog cut its foot on splintered granite rocks (on another trail) and needed a lift back to her car 5 mi away. Not a good day to be a 4-legged!