Heading north from Kansas City on the expressway, I usually take the first exit over the Iowa state line and go about 4 miles to a county park/CG called Slip Bluff. Very peaceful, and you can walk a few yards to the edge of the bluff and see about 2-3 miles north in a valley. I think the most other campers I've seen there is 5, and one time I had the place to myself.
But when I camp there, I'm always on my way to or from someplace other than Iowa. Like Minnesota or Michigan. Iowa has never been my destination.
US 151 from Cedar Rapids to Dubuque, and continuing on into Wisconsin, is a pretty drive with rolling hills and pastures.