WeekendPack, glad you got some good recommendations here. I'm a bit wary on your visiting Death Valley in August. Best times are late fall through mid-spring seasons. If I was going through DV in August, I would leave Las Vegas before 4 AM, so I could make it into DV about dawn. (The views with the early morning shadows would be outstanding at that time, too!) See what you can, and then get out of there by noon. You won't want to step out of your air-conditioned car when it's 120F outside.
There is a daily lottery for Half Dome, so you should get into that if you don't already have permits. You put in 36 hours before the hike and see the results next day if you get a permit or not. If you don't get a slot, you can always climb Clouds Rest from the Lake Tenaya trail head, and look down on Half Dome -- it's quite a spectacular view.
You should be working on overnight accommodations already for your stay around Yosemite.
