My parents are in Decatur, IL. I take I90 to Sioux Falls, SD, I29 to I80, just N of Omaha. I 90 is a wide open route. You can take it easy or fast without a lot of traffic mess.
May God bless your travels
Me, The Wonderful Wife
and two Spastic Border Collies U.S. Army Retired 2004 Coachmen Aurora, 3480DS 2007 Saturn Outlook, FROG
If by easier you mean fewer high mountain passes, I would say I-90 is the easier run. Stick to the interstate and you won't encounter anything steeper than a 6% grade. However, those grades can be very long (like 10 miles sometimes) and are tough on equipment. I can't tell from your post what rig you will be driving but take care of your brakes on the long down grades (don't "ride" them, use short firm application, keep your speed down, use lower gear). Keep your engine cool on the long climbs (lower gear, lower speeds).
If you really want details, get a copy of Mountain Directory Guides . Check out their website then order a copy if you think it will be helpful..
Tom & Jan
Full timers since April '06 - 2 fur kids (George - mini Aussie, Archie - mini Poodle.)
2006 Beaver Patriot Thunder towing 2012 Subaru (4 down)
Started workamping Sept '07 - "This isn't too bad. Think we'll do it some more."
Just for laughs and giggles, you might drop down to US 20 - longest highway in the US. Runs from Newport OR to Boston MA, coast to coast. It is the E-W highway through Yellowstone, than on to Cody WY and so on. Last year on our return from AK we came down from Glacier NP to Yellowstone and drove US 20 straight through to Rochester NY. In IL we did jump off onto I 80 as surface roads through Chicago did not seem the wisest idea in a 36' coach towing.
Lots to see along the way and very little traffic. Iowa was a bore, mostly (sorry to you Iowans, but it was our experience). Great free and cheap town parks for camping along the way.
Paul
Trucking down the road in our new Phaeton 36QSH on Freightliner Chassis with a Cummins 380 pushing it. 2011 Cherry Red Jeep Wrangler Rubicon with US Gear Unified Tow Brake System. Check out my blog
FMCA 352081 SKP# 99526
No question I-90. Pretty easy drive. I-90 in eastern Minnesota was horrible but I think they were working on it. Not sure if construction is finished. Perhaps someone knows. You could drop down I-35 to I-80 to Illinois as well.