“Let’s say 10 miles per generation, as these people are hunters and gatherers and would need a territory large enough to support themselves.”
Might the plains Indians, before the arrival of horses, have some similarities to these people? If so, a band might need a lot more than ten miles.
Yes, in a climate less populated with animals to hunt, and fewer nuts, berries, tubers, etc., to gather. The hunting territory would have to be much larger.