I have no idea what sort of 'eats' will be available at a Carnival in Illinois, but what I would do is make sure I take some 'emergency rations' with me in case I can find nothing 'legal'.
For induction I used to make cheese 'crackers' as they travel well without refrigeration and maybe pack some chopped up veggies and a dip of some kind. Another idea is SunnySmile501's crispy crackers which I will post the link to when I find the thread.
http://www.atkinsdietbulletinboard.c...ng-crispy.html (Craving Crispy)
Will there be any normal fast food outlets serving foods? One of the sticky threads in the induction forum gives some company websites where you can plan in advance which of their dishes are most suitable.
http://www.atkinsdietbulletinboard.c...nfo-links.html (Restaurant Nutritional Info Links)
Above all do make sure you take a large water bottle with you so you don't get dehydrated!