Or splits off, depending on which direction you’re going. 
I like to stop at the National Wildlife Refuges in the Central Valley. There’s two near Los Banos (San Luis and Merced), Kern NWR by Wasco/Lost Hills, and a little one at Pixley that I’ve not been to yet. They usually have an auto tour route, and offer great views of the migrating birds of the Pacific flyway. If you’re there at dusk, San Luis is an amazing place for owling.
I grew up in the central valley and you guys are giving me flashbacks. I am confused by the comments about stopping in the tule fog to wait for it to pass. I don’t remember it ever passing when I lived there. I would sometimes last all day, not roll in and then out like a rain storm. Or have things changed lately?
Still have a vivid memory: when I was little we lived next to a horse pasture. The horses and cows had walked trails in the grass in the pasture. One super foggy day I had to walk a friend across the pasture to her house on the other side after school. On my walk back, I noticed that the fog was so thick I could hold my hand out in front of me and barely see it. I got home by following one of the cowpaths.
It’s been absent for the past several years. It did make a return this past winter but almost only in the morning.
Only a few days of near zero visibility but .25-.5 mile was common. Usually by midmorning to noon it would clear to over a mile or more.
We take a trip to Disneyland (from Sacramento) at least once a year. We used to always take I-5, but lately we’ve driven 99 more often than not. It’s not exactly an ‘exciting’ drive, but it’s a lot less desolate than 5. There are a lot more placed on 99 to stop, and the scenery actually changes a bit from time to time.
The one major caveat, as others have already mentioned, is fog. If there’s tule fog forecast, then avoid it like the plague. Though I understand that climate change has drastically reduced the amount of fog in the valley, so that may not be such a driving concern these days.
The drought has decreased the tule fog significantly.
Fresno has Forestiere Underground Gardens, an underground mansion/hobbit-hole and garden hand-built by one dude.
Directions: Exit 99 at Shaw in Fresno, head east a short distance (I think it’s about a mile, or maybe less), and it’s on the right. (ETA: From the outside, it looks like a large mostly vacant lot, with some scruffy shrubbery here and there. That shrubbery is actually the tops of underground plants, sticking up through skylights from Level 1 below.)
Open for public tours, but reservations or appointment required, I think. Their web site.