I've only biked at Starved Rock -- it's just off the I&M Canal trail, which is a great resource though it sees a lot of traffic from Chicago. Are there some good class 3 scrambles for the whole family?
As for new Midwest items on SP, I've recently added the topographically insignificant Spirit Mound, SD, which is nonetheless a pleasant bit of native prairie with great views. You flatlanders know what I'm saying.