We ended up going on May 3 because we already had park tickets for the 4th. The crowds were great because starting at 9 the park is only open to people who have tickets for the event. You can go in at 6:00 while there are still other guests in the park, but at 9:00 everyone else leaves.
We didn't do any of the autograph or photo lines, just wandered around and enjoyed the atmosphere and went on rides. We did watch the Star Wars fireworks and go to the light saber meet up, which were both amazing. There was a really cool dance party on Main Street. Alot of people wore costumes which was really fun. We dressed up, too. It was worth it for us and we are planning to go next year, too