October has progressively gotten to be a lot more busy over the last 5-7 years. I think between the halloween parties, columbus day crowds and states with fall breaks, it's a mixed bag. I think sticking to earlier in the month is always a little lighter than closer to halloween and of course, if possible, avoiding weekend crowds. Crowds are very finicky from park to park, it can feel like there's nobody at MK and on the same day DHS feels shoulder to shoulder.
My general rule of thumb is we avoid MK on Mondays and Saturdays-DHS is always a slammer so unless there's a reason to be there like EEH, we usually use DHS as our wildcard and go when we want to, Epcot is a usually busiest on the weekends so we usually make this our weekday/non holiday park and AK is always the least busy so this can be a Saturday/weekend park without any real issues or fit into the schedule as needed. I do watch the touring plans crowd calendar not so much because it's really that accurate, they're never that great, but it does help with keeping up with events, park hours, fireworks, etc.