Indiana will do that to you.
My group was in, err, very good shape by the time we got to Kansas.
We crossed Indiana in less than 2 days of riding (Vincennes, IN to Cincinnati OH along Hwy. 50). It was exhilarating.
They went to Alaska, had some fun times with Canadian customs for not following directions. And they thought they took an excess of spare inner tubes and made it about halfway before needing to buy more.
My Indiana comment was more a “people from the Midwest will take any opportunity to make fun of Iowa, and if that’s not an option, make fun of Indiana or Wisconsin”
I personally can find flat farmland quite beautiful, but I can imagine biking through it for days might get dull.