If your interested in riding on rails to trails paths i cant recommend Madison enough as a starting point enough.
You have the Military Ridge and Badger trail all starting here. From there you can branch off to the Sugar River. The Glacial Drumlin starts is a 10 minute drive from the city and the Elroy Sparta area is 45 minutes.
If your interested in riding on rails to trails, check out my blog. You can find maps, photos, etc for many of the trails near the Madison area.
http://bartsbiking.com/