We will be there too that same week. From what I have read the closer you get to alloween the busier the MNSSHP.... I have my party tickets for the 23rd (day we arrive). I am also thinking with all the parties scheduled that week that the rest of the parks should be on the quieter side... (or so I'm hoping!)
We have been the last week of October for the last 2 years and it is wonderful. The party is somewhat crowded but nothing you cant handle. You will have a great time.
We were at WDW Halloween week in 2004. The begining of the week is much less crowded than the end of the week. It was busier than what we had expected but not unmanageable.
We have been in late Oct. many times. It's our favorite time to go! The weather has always been great and crowds more than managable. But...it seems that crowd levels have been higher this year in general, and the Food & Wine Festival has become more popular. So we may be seeing a bit more congestion this October. We have MNSSHP tickets for the 25th. I'm sure we'll manage and have a great time.