Illinois is still recognized as being one of the best places to hunt truly big whitetails. However, things have changed dramatically over the past 10 to 15 years, and not for the better. The area you are talking about is a nice area. Getting a place to hunt will be extremely difficult if not impossible unless you are open to the idea of getting in on a lease. Even this will be difficult.
Deer numbers in Illinois are down from what they were even 5 years ago, as per plan by our DNR. The real problem though is that quality is suffering. Yes we still have some huge bucks, but not in the numbers we used to have them in. Liberal seasons, and the fact that both residents and non-residents can kill 2 bucks a year has had a definite negative effect. I believe Iowa gives out like 11,000 non resident tags, good for one buck? Illinois has been giving out like 24,000 the past few years. And this is just archery tags!
So, the hunting here is still better than most areas when talking about quality whitetails, but not nearly as good as it was. Honestly, at least as far as hunting goes, I would want to stay in Iowa. Good luck to you either way!