I am glad you managed to get an extra night in as it was quite clear you wanted it to happen. Without trying to put a 'downer' on it, You will still have 2 long days but it is achievable.

Personally i would try and get an early start from San Fran to Big Sur which will make you feel less rushed and more relaxed and would be looking to stop in the Bakersfield area. A possibility would be to travel on HWY 178 from Bakersfield to Lake Isabella for the night,which would give you a good start the following day as you head for Ridgecrest and onto Death Valley