It will be pretty busy. October used to be great crowd wise, but more and more schools have fall breaks in October and it is getting busier every year. Food and wine festival also brings a lot of people. But, it's still a great time to visit!
The closer to the holiday the busier normally. It will be busiest on the weekends though. It is certainly doable from our experience. There are more families than in the past since a lot of schools added a fall break.
A good time to test the new FP+ and sees how you like it!
If you've been in summer you will be thrilled with how low the crowd levels seem! We went Oct 25-Nov 7th last year and similar dates the year prior. It's our fave time of year to travel for crowds and weather.
The most crowded area is the food and wine festival. We tend to go right away in the morning when it opens or later in the evening for Illuminations but skipping out on the 2:00-6:00 time frame.
We didn't ride any of the big kid rides so can't comment on that but things like Dumbo when we went early in the day or late, we could ride 2-3 times without getting off the ride. The longest we waited for rides was 20 minutes but for rides like Little Mermaid it felt like getting right on because you spent most of the time navigating the que.
In our experience, it is not even close to summer crowds, especially during the week. It tended to get busier on the weekends, but nothing compared to June. I think you will be pleasantly surprised at the lower numbers of people.
I will caution that the booking lines have been jammed since they announce FD and a RO discount so it may be busier than it has in the past, but no one but Disney really knows. If it's anything like in the past though, most rides are walk on to 20 minutes. Except the usually long one of course. PP, Soarin, TT, TSMM, etc....
There is a huge difference between the week the week of 10/18 and the week of 10/25 now. Many schools are on break the middle weeks of October (we get two full weeks now) and it has been getting crazy busy, but clearing out around Halloween because schools are back in session.