Central Illinois through Iowa to Minnesota

Good plan. Us20 is great. Enjoy the trip

There's something to be said for getting off the interstate now and then. FYI, I-80 can get pretty busy between the Quad Cities and Iowa City.

When we head west from the South burbs of Chicago we take I80 to I380 north to US218 to US18 to Clear Lake and I35. US218 and US18 are four lane divided with bypass around all the little towns. Mostly light local traffic.

I-80, I-380, US-20 is viable.
Some input on the I-380 stretch:
1) Watch time of day - commuters can/will make your life hell. Rush hours are 7:30-9:00am and 4:30-5:45pm, M-F. Avoid those times.
2) Very nice rest area 10 miles north of 80/380 interchange.
3) Ketelsen RV shop is marker 25 on 380 (in case you need something).
4) Center Point travel plaza at marker 35 - RV friendly for gas (also has a McDonalds, Subway and Fireside Pizza - good pizza).
5) Lazy Acres RV park at marker 41 - decent overnight spot, not much else.
6) Like whacky stuff? Hit exit 49 (Brandon) and you can see the state's biggest frying pan. Yep, a huge frying pan, 14 feet from handle to rim, 1200 pounds. Why? It's Iowa. We also have ghosts playing baseball in the corn fields, so...

Regarding HW20 across Iowa. We took this road in Sept 2015, driving east. This road looks pretty good, however, the expansion cracks perfectly matched our truck/trailer combination's wheelbase and pounded us non-stop for several hours. We finally turned south on 380 and then back east on 80. On the way back west we stayed on 80 rather than risk that HW20 would be the same in the westbound lanes.

From the replies it looks like it is certainly doable, and looking at 27 up to 18 and across to I-39. Quad Cities to Cedar Rapids looks like the high traffic section with the rest being pretty decent. If that is true I figure it would be a good trade off with the alternative being Rockford, Il and the toll road up through Madison, Wi. Not my favorite stretch by any means.
I also guess the southwest section around Minneapolis will be better than the north side coming in on I-94. Time of day is what it is. I am retired but wife is not so we have to leave when we can and sometimes that timing works out and sometimes it doesn't. Don't figure it will be worse than Nashville or Atlanta and we have hit both during rush hour. Jim.