Hi there - I'm a LA-Vegas-San Francisco veteran so here is my info:
ok from LA to LV if you take the freeways (10 to the 15) it will take 4.5 hours.
If you take the Pearblossom highway shortcut, it will take 3.5 hours (the 405 to the 5 to the 14 to pear blossom highway to the 15) but I don't suggest pearblossom unless you are a risk taker and familiarize yourself with the map because there is alot of construction there and you MIGHT have to detour through Victorville. In any case, I love getting to vegas in under 4 hours so I take pearblossom all the time lol.
ok and from vegas to san fran will take approx 6.5 hours from bakersfield to san fran through the 5/grapevine. it's an ugly drive, but the best straight through shot.
Whatever you do try to avoid a holiday weekend because you will sit in traffic for hours. My ex and I drove from LA to Vegas a couple years ago on the Friday morning of a long weekend and it took us about 8 hours to get there with the traffic. We were planning on driving home Monday night but ended up staying until Tuesday night because we didn't want to sit in traffic on the way home too.