Katy Trail East end to Northern Indiana

[Papa6k]

A few years ago my wife and I had to stop a ride duet of pa medical issue. We are now ready to finish the last 500+ miles. Our ride will be non supported. We want to go from the East end of the Katy Trail to near South Bend Indiana. I am interested in any suggestions for a good ride through IL. We will most likely ride  an average of 50 miles a day, depending on hills and wind. Thanks in advance for any suggestions. I am not sure about hook ink up wit Route 66.