The Kishwaukee River south of Rockford has great kayaking for people of all skill levels. I went with my sister, her husband and their two boys. The almost 9-mile length was a little long for the younger one, but with a current that keeps you moving in the right direction, it seems shorter. And there are plenty of sandbars to take snack breaks.
My sister’s family has done this kayak several times, and she says the water level has varied considerably. When I went with them, she said it was much lower than her previous trips. We had to hop out of our kayaks and drag them a couple of times when the river was too shallow, but it was manageable and only happened two or three times.
Time lapse video of the Kishwaukee River: