I am from Illinois and I do know the law. If you have a CCW from your home state you may carry concealed inside your vehicle. As soon as you step out of the vehicle you are illegal, pretty simple really. If you want you may place the loaded firearm inside the console or glove box but I would never place it where you have insurance or registration papers. If you leave it in the vehicle it must be secured by locking inside a case or locking the vehicle. If you want to take the firearm with you it must be unloaded and inside a case before you exit the vehicle.
I know there is no logic to any of this but the law was not intended to be logical or keep people safe. This was passed because the federal court of appeals told the state they could not no longer make carrying outside the home illegal. Jim.