Can anyone explain the walk-in permit policy from happy isles? I would like to begin my JMT hike in July, and I've recently come to realize that a reserved permit needs to be set up 24 weeks in advance. I'm obviously too late to do this... If I have a very flexible start time, two days or so, when I get to Yosemite, can I count on being able to get a "first come first serve" permit?? I'm confused...