I live by the Canon Valley Trail which I know very well. This is a pay-to-use trail so having the Root River trail be state managed and not have to deal with buying a pass is a bonus to me (guess I'm already paying for it!).
The trail is nice in that the towns on it all have nice stops and easy places to park. Also, much of it is not very steep so it's easier to bike with young children.
There are some campgrounds on or near the trail if you want to do that. I'm a fan of the state park system - Forestville is nearby and wonderful, but about 8-10 miles from the Preston trailhead. Certainly worthy for a family trip or for couples, too.
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