Be aware you'll run into rush hour traffic on your way to SF after 3 pm.

Thanks for replies.

Unfamiliar with sf traffic, how long am I looking at to get into union sq would you think? Or how long would the traffic increase my journey by?

Thanks

http://goo.gl/maps/8ZZl5 It is over a 3 hour drive without heavy traffic and you can avoid most of it by leaving around 1pm. and by taking hwy 280 as shown in the Google maps. You may hit some closer to the city if you leave later say about 30 mins or so not much more if you want to be there by 5

You MUST leave the Big Sur area BY 1:00 pm or you won't make it to SF by 5:00 pm!! Get an early start in the morning to maximize your time.

The fastest route back to SF is Highway 1 north to Highway 156 East to Highway 101 north to Highway 85 north to I-280 north. Sounds complicated, but it's not.