The 3 indoor parks I can think of in Northern Illinois WARP, Krush, and Elk Grove Village dont allow scooters, but 4 seasons in Madison allows scooters.
If you live near springfield (please tell me you do, i really need someone to ride with) there's a skateshop called 2one7 that has an indoor park. It's not really very great but we don't have much better here by springfield. You have to pay though.
Theres one in loves park thats outdoors forget what its called though.. Theres a sign that says electric scooters arent allowed so youre gonna get bitched at if you ride there cause skaters are dumbasses.. whatever lol.