I drive over and head up the first night to Horseshoe Meadows. Getting there after 10 pm is my goal. Just walk in (campground area on the south side area) and find any flat spot away from others and sleep. Next morning you can break your simple camp, drive down, pick up hiking permit in Lone Pine, then head up to Whitney Portal and set up for a second night there.
There are the Ravine area walk-ins, and there are the walk-ins just below the trail head parking area. You can pretty much always find spots, especially if you get there by noon.
