Cheese,
I think I tried to answer this in another thread, and didn't read it right anyway. My stab at the answer is that There are some very good counties in the far south - like Pope, and others in the Shawnee Natl Forest. Central Illionois has some exceptional counties from Indiana to the Mississippi River - particularly around Peoria to Pike County. Northwestern Illinois - Joe Davies, Carroll counties are very good. Finding a place is tough unless you have deep pockets..