Years ago, BK (Before Kids), dh and I drove leisurely from So. Cal up 395 all the way to Lake Tahoe and back. If you like great scenery, it was TOPS! The craggy Sierra-Nevada mountains to the west, the desert to the right initially, then it changed to semi-arid -- we saw deer grazing as we approached Mammoth Lakes (a whole wonderful side trip in itself), passed Mono Lake with its eerie tufas, stopped at Native American trading posts, took a side excursion through the narrow valley of June Lakes Loop,--- then, Tahoe was gorgeous, as ever. We would have driven to Bodie, the ghost town, but we'd already done that on our honemoon. Too bad you're not wanting to travel in Jan; I hear Death Valley is an incredible sight (Scotty's Castle, the moving rocks, the lowest elevation in the US, etc) but you have to go in Jan or Feb.
Friends just returned from driving thru Monterrey Bay area, and some of the State parks up the CA coast, and just raved about the area.
Then there's always San Francisco! Ghirardelli Square, the famous trollies, Pier 39, Alcatraz Island, ferry over to Sausalito, the Golden Gate Bridge, Muir Woods (which is over the bridge and north of the city area; gorgeous stand of sequoia trees, with lush fern carpet, and well-maintained trails for strolling), Golden Gate Park (Steinhart Aquarium, Natural History Museum, etc etc).
We haven't traveled very widely, but the above places are some we thoroughly enjoyed.
Good luck with choosing, keep us informed (cuz we're nosey?? Nah, just because you may enjoy a trip and share it and someone else may choose to enjoy it as well, just from your recommendation!)