OK...got some more info for traveling through the Peoples Republic of Illinois.
Found this on their website.
Q. If a non-resident is coming to Illinois to hunt and would like to bring their firearm, how do they legally transport it?
A. Non- residents must be legally eligible to possess or acquire firearms and ammunition in their state of residence. It is recommended that, in order to be in compliance with all statutes, non-residents transport all firearms:
Unloaded, and
Enclosed in a case, and
Not immediately accessible or broken down in a nonfunctioning state.
Q. Is it legal to have ammunition in the case with the firearm?
A. Yes, so long as the firearm is unloaded and properly enclosed in a case.