We surprised our 3 kids (ages 13, 5, and almost 3) with a last minute trip to WDW. The highlight of the trip was MNSSHP. I highly recommend this to everyone. The kids loved all the special effects, parade, fireworks, trick-or-treating, etc.
Until I started reading this site I had never heard of MNSSHP. I'm glad to hear you had a good time. I think it would be really cool to be there at Halloween and also Christmas!
We're thinking about spending a week at Christmas, but I'm not sure we're up for the crowds. Last week was bad enough -- far worse than the end of May or end of July.