yeah, take the interstate 5, which cuts through the middle of california. it ll take you between 5 or 6 hours to do the trip, assuming you stay around the speed limit. you might also consider flying. southwest airlines usually has some pretty cheap deals, and the airtime between LA and SF is usually about an hour.
Then you should fly. To go by road, you will have to be heading north by 3AM to make it in time. 4AM at the absolute latest. Take the I-5 north intil you see the signs giving you the exit to San Francisco.
Take the 5 freeway. It is about 5 - 6 hours from LA to San Fran. Don t take PCH - it will be scenic but will take forever.
Quickest way is to fly. If driving, quickest way is I-5.
The I-5 SouthThe US-101 (scenic) would take way to long
I-5
I-5... about 4 hours