Looking for Farmland to hunt on in Kane County
Go to the county courthouse and get yourself a plat book or download a landowner map app like "OnXMaps".
Right now while the weather is mild and geese are still around in big numbers, go look for properties they are on. They may or not be there next year but they'll likely be somewhere close. Also find roosts, not to hunt but to know where concentrations of geese are so next fall you can find a central location where they come and go from.
Make some contacts with landowners now and into the spring. Offer your help if it's likely they'll let you hunt. Don't bother them during planting time. Considering the location to a large population if you wait until summer to make contacts, you'll likely be making contacts for the 2017 season. Be prepared to be rejected about 30 times to one who might let you hunt. You're looking into a high pressure area and contacts and relationships will need to be made well in advance of the season starting.
You're other options and likely easier are to hire a guide or make some friends who already have access. Do not ever go back on your own to private land that someone else took you to unless the person who took you is agreeable to it. Nothing would get you cut out of my loop than to return to a place I took you to originally. Frankly if you're just starting out, you'll be far better off going with someone experienced than to go try to learn it on your own. You're looking into a high pressure area with pressured birds that won't cooperate nicely with a novice. Learn how and get some success before you beat yourself senseless trying to wing it on your own.
I'm not sure about IL but WI has a learn to hunt program where you and you kid would take a one day class and then follow it with a hunt with an experienced volunteer.
I'd also highly recommend an afternoon with a shooting instructor if you or your kid don't have much shooting experience. It's easier to learn how to shoot the right way right off the bat than to develop bad habits.