splake, eje67, UglyOldMan, LuvAdventure2014:

If you see slots available for any of your choice of dates, it is my guess that people have already cancelled the slots they won. It is highly unlikely that any dates in June through September had any remaining slots left after the lottery process ran. Also, when you talk about seeing slots available, make SURE you are looking at the overnight or day use displays.

Those slots that you can see will become available at 7 AM on April 1. But good luck, since they vanish in seconds. You are likely to have better chances on May 1.   On April 1, using the recreation.gov website to grab available slots, you will have better chances of success if you practice: Click "update availability" repeatedly until the 7 AM time they show available. When the "A" for available shows up, click it, then click Book Permit -- as fast as you can! Make sure your group size is already set correctly.