It is very surprising how hot and dry Yosemite / King's Canyon / Sequoia are in the summer, and you might bring asbestos lined shoes if you plan to get out of the car in Death Valley, AND the drive north observation is astute, but . . . if arriving in LV and departing from LA, I think I'd prefer the counter-clockwise approach.

Of course - you can do a bee-line (sp?) from LV to LA in about five hours I think, then have lots of time to decide how far to go up the coast, or inland to Napa or Joe's wildflowers. If you can still leave from SF instead, it would give you a lot more freedom.

(Not that driving both up and down the coast would be a punishment or anything.)