Route 20 is OK, once you get west of Elgin. Before that, you're stuck in traffic. The only really decent routes as alternates going west would be I-88 to rte 47 north to rte 20, or I-94 west, but I94 is under construction in areas and is slow.
Or, 7pm thru 5am on rte. 20, but watch out for deer!!!!