Assuming HalloweenTime has started, my guess is that the weekday mornings won't be too bad, but there will be crowds in the evenings and on the weekends (Fri to Sun). If you can make it to the parks at rope drop, I think you can get a fair amount done in the first part of the day before the after school/after work crowds start to arrive into the parks. If Mickey's Halloween Parties have also started (which seems likely, but they probably won't announce the dates until mid-summer), then the afternoon of the parties will be busy (especially during the overlap period).