I just plugged our dates on for the Halloween party 9/25 and it's sold out
How crowded will this be, this still is early in the season, wow!!
I was at a sold out party last year and I really enjoyed myself and found it to be crowded in the bottle neck spots (the entrance areas to tomorrow land and frontier land and on main street around parade and fireworks times) but otherwise not crowded looking at the park and experience as a whole. A friend from work was at the same party and said it wasn't fun, it was too crowded and it was her last party. Why the difference 1-expectations and 2-touring plans
1. I hit the treat trails only after the fireworks and there were only short lines that moved quickly.
2. I got my spot on the curb near the little Red Wagon a little less than an hour prior to the show and we ate dinner alfresco curbside so the wait didnt seem bad to me.
3. I used a blanket and a stroller strategically to help keep a space bubble around me while waiting for the parade. I didnt feel crowded at all.
4. I got there well before the toontown preparty to get my a couple of fab 5 in costume must do photos and my magic shots done so I didnt have to do them when all of the party goers were there (this only worked for me because I had an AP so I was able to enter early unlike people with just a party ticket)
5. We focused on rides quite a bit and they had very very short lines so we felt thrilled by that
6. We skipped the Halloween themed rides during the party because they tend to have a longer line during the party than during the rest of the day. I did HM and SMGG during the day on other park days,
7-the Most important-If I saw a crowd or a long line, I turned around, walked away and did something else and came back and checked on it later near park closing. (This will not work for characters FYI)
So if you adjust your touring style and expect to see crowds in the bottle necks and near parade routes and fireworks (sometimes very hectic crowds that I refused to trudge through) and have a plan to not let the crowded areas bother you or to avoid them as much as possible then you will think it was not crowded.