San Francisco is 960 miles from Van City. LA is 1290 miles away. Figure on 14 hours from SF, and 21 from LA. If you drive fast and there's no traffic, and only get 2 tickets and a warning, LA to Van can be done in under 15 hours.
I have driven from Vancouver to Crescent City Ca, right at the California/Oregon border, in 12 hours. Ive driven to SanFrancisco in two easy days, with an overnight stay in southern Oregon on the way down. The Pacific Highway is a beautful trip if you have the time. The I -5 is much faster, but not nearly as scenic.
I have also taken a Greyhound Bus from downtown Vancouver to LA, and it took 32 hours, with short stops for meals and bathroom breaks. It was pretty grueling.