Yosemite itself is fun, but in high summer, you and everyone else in California will be there. The harder you have to work, and the further you hike, the fewer people you will see. Up at the top of Tioga Pass is some spectacular hiking opportunities.
Bodie is fun and worth a day.
Mammoth makes a good stop-it's shi-shi but still has some good places to eat and stay.
The Bristlecone Pine Forest is a good visit, and if you go up Silver Canyon, you can get there on dirt roads.
Ballaratt is not that great, but the canyon just behind it is. (Pleasant Canyon). That takes you up thousands of feet in the Panamints with extended 4wheeling opportunities in Middle Park and South Park. Great views of Butte Valley off the rim of South Park. It will be much cooler up there and a respite from the heat of DV proper.
From there, up and over Golar Wash, Mengel Pass, Butte valley and out into Death Valley itself via Warm Springs Canyon. It's a real adventure and worth your time. That will take at least a day to make the West-East traverse. Not much gas, so plan accordingly. From there, which is kind of the South End of DV national Park, it isn't far over back roads to Las Vegas.
Alternatively cross DV in the North and visit Saline Hot Springs, Ubehebe, and the Race track. It will be hot so plan accordingly.
They have little cabins you can rent too.
