J.L.
Try Brodhead, WI; about 2.5 hours from here. There are bike trails all over the place, and cute little towns (New Glarus especially - like a Swiss town) to explore. There is a bike shop in Brodhead, Earth Rider, that rents bikes and the owner has a bike-themed hotel above the shop. It's very cool, and environmentally friendly. I think there are 2 rooms appropriate for families. We stayed there this summer with our 2 girls (5 & 7) and we all loved it. The bike shop is right at the trail head of one of the trails, and many of them intersect.
Have fun!