Unless you want to backtrack, after getting to San Francisco, going to Vegas from San Francisco is quite a long drive across much, dry desert. If you go that way, be sure to have gallons of water available (for you and if the car overheats), easily bought at any store, and be sure to keep the petrol tank filled as well as watch the water in the radiator. With a rental car, it should be fine, but it's just not anything you want to be without on such a drive.

We have several members who live in California, one of whom sings in a chanty group on the ships in San Francisco. I am sure they'll be along with more specific info. I would only add, that, if you get a chance and are interested in Egyptian artefacts, there is a lovely museum in San Jose: HERE which has the largest collection on exhibit in western North America.

Have fun!