We avoid St Louis and absolutely stay away from Chicago. If you want to stay on Interstates I'd get on I-74 in Cincinnati, follow that west to I-80 then turn on I-29 up to I-90.
We actually get on secondary roads off I-64 before East St Louis to Keokuk Iowa, cross the Mississippi there then you can go north on secondary roads to I-80 in Iowa. We actually cut across Iowa on secondary roads all the way west thru Nebraska then up into the Badlands from Nebraska. You see a lot more of the country that way. Go thru Wounded Knee for one thing and past 150 year old forts in Iowa.