We went on Halloween party days last month. I did one day with LLMP and the other 2 without. Honestly, I think you can probably go without it, but it definitely made the day easier on the day we did. We did a ton of rides and many we were able to get with almost immediate return times for the LL. The other days we also got a lot done, but did have a few waits that we did not have on our LL day. I did pay for Tron on the one day we were there too. We do not wait in long lines because of my Mom and were denied
DAS for her, so we did skip Peter Pan, 7 Dwarves, and Tron standby.