PCH is a great drive, but slow. There are some great sections of it but again it is slow so it takes time. I personally am not a SoCal guy. I grew up in the Santa Cruz mountains but I have driven all of Hwy 1 from Portland to where it turns into the 5 around Dana point. I think the So Cal part of the 1 is Historic but there is traffic and I don't personally find it to be all that Scenic. The portions around Santa Barbara get better but for me the good stuff starts around Morrow bay. Big sir is very pretty, but for me if I wanted the full peaceful coastal experience I'd probably do from SF north, it is so pretty that direction. As someone else said the 1 running even further north through Oregon is amazing it starts to look like Maine or something up around that Coos Bay stuff and the dunes look cool. There are little lakes and streams on one side of the road with the ocean on the other and it is so green. I grew up right on the edge of Big basin Park, that is a pretty cool area and Big Trees is great as well. I am not sure what you will be driving but the lost coast north of Fort Bragg is a neat area but you need a high clearance vehicle.
Yosemite is beautiful but can get very crowded. it is not as busy up top by Tuolumne Meadows but that isn't the quintessential Yosemite view, a great spot for the drive up view is Glacier point, all hikes in Yosemite require at least 5 miles before you start to lose some people...before that its mostly paved walks crowded like a city.
I live in Reno/Tahoe now. Tahoe is worth a look for sure, the section through emerald bay being probably the most scenic. Save a little time for a walk to the water or a stop. Great swimming holes on the east side. The water is very clear and you can see in it quite a distance. It is always cold, its a good swim but cold. Most the other Reno Tahoe stuff involves more of an activity like riding dirtbikes, boating , fishing, etc...or gambling of coarse. Not sure what your after there. Virginia City is kind of cool...sort of a leftover gold rush town, wooden sidewalks etc. Pyramid lake is amazing, also very clean, it's on Indian Reservation. It's in the middle of the desert so its one of those "really there is a lake out here?" and then you see it...almost the size of Tahoe, great wake boarding when it lays down which is often, great place to sink a boat when the wind comes up that is also often. Some great Hot springs around in Nevada...again not sure what you are driving most are high clearance. Hwy 395 from gardnerville to about Ridgecrest is very scenic.
Utah I love, for me Zion is my favorite but I like driving in Utah a lot.