...from the beginning of Ohio to the end of Iowa, that isn't corn, is soybeans. Might want to plan on night passage through there.
Rode "The City of New Orleans" from school to Chicago & back a few times, just the length of Illinois so no sleeper, and personally you couldn't get me to do that again for all the money in the world.
The western quarter or third of the trip I'd do but I would fly to Denver then get on the train. Good luck on your adventure!