This past Halloween, we were there on a (rainy) Thursday in September and then again on Friday, Oct. 22nd. While the park was empty when I went in September, it wasn’t bad at all the week before Halloween weekend, if you plan it right.
On Oct. 22, we planned on only doing party activities and skipping rides (expect for HM) and were were able to hit all the trick or treat spots, make all the special meet and greets, spend lots of time at the dance parties, see the parade, the fireworks and soak up everything that night.
We arrived just at 4pm when we could enter with our hard tickets, got our wristbands and took lots of pictures. We lined up at about 6:30 pm to see the 7 dwarfs (and were the 3rd family in line) and we choose to wait until after midnight to enjoy main street and take more photos.
Just to let you know, my children, along with many other children in the area have several days off in October and a lot of local people attend MNSSHP. I recall there were 2 Thursday nights in Oct. 2010 that were sold out. The friday night we attended in Oct. was not sold out.