K.C.
It's not super scary at the park in general. They don't have people jumping out or chasing you the way some of the other theme parks do for Halloween. It's not Haunted. Haunted Mansion can scare kids anyway, even when it's not done up for Halloween, so I'd probably avoid that one if I were you.
I haven't been to the Halloween party before but I did buy tickets this year. They limit the number of guests at the park, so I would have thought it wasn't as crowded, but the previous poster said it was so I don't know. You get to go on the rides and trick or treat at certain spots throughout the park. Kids and adults can go in costume.
I doubt World of Color will be changed since it's such an elaborate show. In my opinion, not worth it. My kids, my friends, their kids and I were all bored.