SF is one of my favorite cities (to visit :-)). And there's tons of other great stuff to do within driving distance from 1-2 hours on up. (You can reach the Sierras but I probably wouldn't recommend that for a first time visit of limited duration.) IMO, great choice for a vacation of just about any length.
Oh good lord. Not even close. Maybe Las Vegas is a bucket list sort of thing to do once for a few days. (I, sadly, have spent a great deal more time in Vegas than that.) There are very interesting places within a few hour radius of Vegas if the weather isn't too hot--Death Valley, Zion, Red Rock Canyon, Hoover Dam, Grand Canyon. But I wouldn't spend money or time to go to Vegas itself voluntarily.