Climb away east from the Mississippi River and head to Madison thru Wisconsin's Driftless region. Rail trails make up the latter approximately 70km of the route's total 160km into the capital city, with 59km of that unpaved on the Military Ridge Trail. Note that WI requires rail trail cyclists to purchase daily ($5) or annual ($25) trail passes, with a $5 penalty if not purchased prior to using the trails: https://dnr.wisconsin.gov/topic/parks/admission/trailpass