You do know that Indiana State Parks are open all year. They just turn the water off. You can continue to go camping at the State Parks, even in the snow. Just cart your own water in and use the out-houses, or get a port-a-potty inside your camper and dump it in the out-house.
No reason to call it quits. Just pull in, pick a spot, set up camp, and have fun. DNR will come around to YOU and collect for the night. It's easiest if you pay cash. If they do NOT have a DNR uniform on and are not driving a DNR vehicle and do not give you a receipt, don't give them any money.