Hey welcome to Illinois. I'm a couple hundred miles north of Pike County, next to the Cheddar Curtain. End of October is usually decent still, even way up here.
Definitely bring some good rain gear. We get some of those rainy fall days that leaves a good chill in your bones. The type of rain where it seems to last all day/night sometimes.
It's usually not to cold otherwise..only occasionally do kids have to trick or treat with a heavy coat or ski hat.
I hunted Pike County in December maybe ten years ago. It was chilly but not too cold...maybe low to mid thirties during the day and upper twenties at night. That was right around Christmas.
I've also hunted Jackson County (east and south of Pike a bit) during the second firearm season which is the weekend before Thanksgiving.
Once it was in the forties other times it was in the upper 70's if not 80.
So basically I guess I'm saying expect any type of weather but I would guess more pleasant than brutally cold.
If your driving up and have room then I'd bring a ground blind. Always good to have an extra trick in your bag. This way you have it if you need it rather than wishing you did. If you don't have room then I think you could definetely do without it...plenty of good trees for treestands.
And Penetrator, it's not that bad here. Just because we had the highest gas prices in the country, Chicago was the murder capital of the country a couple years in a row, they won't get rid of the toll roads, the Chicago Machine wants to take everybody's guns,....
Anyways, good luck and we'll need to see some pics! Even if you don't fill your tag, the weather and leaves should be awesome.