Sonoma and Napa are close enough to SF that should go even if you end up heading south. My favorite is the Russian River Valley area. If you end up heading down the coast, I'd also recommend the Paso Robles area. Highway 1 is a great drive, although you may want a backup plan (101) if it closes for a rainstorm.
Decent restaurants -> you'll find them in Sonoma and Napa, but if you stay in SF at all, tons of them, and you'll want to try to make reservations in advance for a lot of them. Lots of museums in the Bay Area as well.
If you want to maximize your chances of good weather and some landscapes you won't see in France, I'd head to Southern California, and specifically: Death Valley, Joshua Tree, and Anza-Borrego Desert east of San Diego. If you want to head further afield, Saguaro National Park in greater Tucson, Arizona is pretty cool. White Sands in New Mexico is as well, although that may be too far. You could easily spend a week just in Death Valley area if you want to, especially if you rent a 4x4/Jeep locally. Note that all these places are really cool in their own right, but the driving is not particularly interesting unless you like desert highways.
Grand Canyon in winter is a toss-up, weather-wise. I've driven to the area in a day from SF (a long, pretty boring one, mostly on I-5, CA-58, I-40). The roads are open unless there's active severe weather. Unfortunately you'll be in the area when there's the least amount of daylight, so if you want to plan your sightseeing around that!
North of San Francisco... the coast almost certainly won't have any winter-weather problems, but it does get pretty cold and rainy. The big redwood groves in far northern California are impressive - I've enjoyed the groves in Prairie Creek Redwoods state park.
You might hear folks warn about driving in San Francisco, and it's true - car break-ins are a common problem. The general rule is: don't leave anything in your car at all (not even phone chargers or water bottles, and DEFINITELY no backpacks or jackets), and also don't park and just move things to your trunk and leave your car. (This is good advice for the rest of the Bay Area, and not really bad advice anywhere..... Unfortunately, cars that are obviously rentals tend to be more frequently targeted, just because the people who do this know that tourists are more likely to leave a few things inside. I suppose this is our version of pickpockets in Barcelona or something like that. The other difficulty is parking but this generally surmountable with patience and/or money for a garage spot!