We went last night and had a great time. Being passholders, we arrived around 12:30 as we wanted to see the afternoon (non-Halloween) parade. Park wasn't that crowded, yes, 7DMT had hours and hours and hours to wait for 1:35 second ride, but Space was only 20 minutes, 20 minutes for Big Thunder and Dumbo was a walk-on, really, no wait. By 5PM crowds were up a bit due to both party goers and non-party goers were intermingling. A couple of thoughts I haven't seen posted here:
If you are a passholder, there are special passholder
MNSSHP t-shirts available. A cast member we were talking to noticed the passholder tag on our Magic Bands and told us there were special t-shirts behind the register. I never would have known to even ask. So, we got the passholder shirts, cool. The Emporium started selling MNSSHP stuff around 4PM, but had cast members guarding the area and they only let in people with wristbands in the area.
The radar kept insisting it was going to rain and thunder all night long. Well, it didn't. It rained for 10 minutes around 2:30 and it drizzled around 11:45, other wise, the threatening rain stayed away.
To echo other posters: Don't miss the Hocus Pocus show, the parade and really, whatever you do, don't miss the fireworks. As suggested here, we found a spot in the knoll in front of Casey's and it was a perfect spot. Even 15 minutes before the show there was room to squeeze ourselves in. Don't leave after the fireworks, the lines for rides, special pictures and for ToT become very short. Especially around BTMR as that is the only attraction in that area and it has 2 ToT spots, you can just keep circling these practically by yourself after 11PM and fill up on all the treats you want. Because Splash is closed, it is a becomes very light with foot traffic. There were 5 cast members at the BTMR spot just begging to hand out treats to anyone who happened by. We did a great rendition of Boo! to you (and you and, well, you all know the rest).
We did a few special pictures, those are fun. The ghouls at the exit of Haunted Mansion were killing it. We didn't do any meet and greets. Lots of people in very creative costumes, lots of people not in costume. Saw a great Mary, Burt and Chimney Sweep, some seagulls from Finding Nemo (MINE!), a youngster in a terrific homemade Rocket outfit with a baby Groot on his shoulder, lots of Wonder Women, lots of Star Wars, lots of Avengers. A very fun party, but at the high cost of the tickets, something we won't do yearly.
OWD