We went the year before last and are going again this year. It is a great night out. We all dressed up and that really adds to the atmosphere. There were trick or treat stations everywhere and our kids had loads of candy.
Most people seemed to be soaking up the atmosphere and getting candy so the queues for the rides were non existant. We went on all the rides several times. The fireworks are fabulous. We didn't see the parade but I've heard its great.
You can get into the park from around 4.30pm with your MNSSHP ticket without needing a normal entry ticket. They put all the ticket holders in a separate area when the park closes at 6pmm and clear everyone else out. Then you're right in the park and ready to go when the party starts.