by AlmostThere » Mon Nov 19, 2012 9:38 pm
I think you are misunderstanding the process. LYV is not a "campground" with reserveable spots.
What you need to do is to get a wilderness permit, for backpacking. You need to do this five months before the date you intend to start hiking. When you pick up the wilderness permit in person at the wilderness office, you will tell them that you want to summit Half Dome, and they will stamp the permit for that. If the permit says you can spend the first night in LYV, that's where you camp - walk in and select a site.
You can specify second and third choices on the wilderness permit application, too. So try to get permits for the passthrough toward Clouds Rest or Sunrise, and then camp not at LYV but farther up the trail toward Clouds Rest, then backtracking a little to do Half Dome. Or, get permits from Sunrise trailhead to the valley floor, take the hiker bus up there to start, hike to Clouds Rest, visit Half Dome, and stay in LYV on the second night on the way down.
Remember - if you camp anywhere other than LYV you need a bear canister. They'll rent them to you (or you won't get a wilderness permit).