I duck hunt with my lab in ND, and have not had a problem with ticks. I think they are usually gone by Oct. If your worried about it you could give them a dose of Frontline before you head up. As far as they weather is concerned, the end of Oct. is usually a great time to be in the field in ND. The really cold air and snow is a couple weeks away, but it' s still cool enough so you and your pup can walk all day without getting overheated. But you never know- last year most of the potholes were froze solid by Halloween.