Pooja Aggarwal at the Beyond Here blog took the short drive up to Yosemite from the Bay Area to see the fall colors and did an awesome write-up of his trip.
Beyond Here: We set off early morning (5 am – I absolutely insisted we leave early) and were inside the park by 9 am. It took us another 30 minutes or more to drive to the valley floor where the color was at its peak. It was stop and go after that even without the traffic – we wanted to stop at each and every bend.
The color was in plenty – the oaks, dogwoods etc. all were showing color. It was a pleasant day too. The colors were being clearly reflected in whichever rivers and ponds still had water (since by fall most of the water bodies are already drying up). We spent a good amount of time in the valley walking around, clicking pictures.