Family fun on the Crystal and Plum Lake trail system is not limited to bikers. Hike, bike, in-line skate or roller ski 15 miles (24 km), one way, through pine, oak and maple forests and along several area lakes on the flat paved trails that wind their way from Boulder Junction to Sayner. Turn the outing into a family adventure: Swim, fish, picnic and camp along the way. Looking for something shorter? Split the trip in two. And depending on the age of the kids, enjoy the Crystal Lake Trail (11 miles one way) one day and the Plum Lake Trail (4 miles one way) the next.