it's not the only way but it is the best way...and shortest with the least amount of tolls and potential traffic. you'll have one toll booth on I-80 as you enter Illinois and expect Illinois traffic until you get past I-355... maybe not until you get past I-55. should be about a 90-min run from the state line to I-39 and another ~90-min to the Wisconsin line. I-39 has no tolls but i can't recall if you'll have one when you pick up I-90.
Rich, Ham Radio, Sport Pilot
2016 Itasca Suncruiser 38Q/2010 Jeep Liberty