Lake Arthur is in Moraine State Park and is home to warm water fish, frogs, newts, turtles, and water snakes. The Moraine State Park Bike Trail borders its northern shores, making for a nice waterfront ride.
I actually rode here and won’t copy paste a tip from some website, who are these people? Park at the far western end of the trail and use the tire pump at the bike rental place to pump your MTB tires up nice and hard. Lock out your suspension and have a blast carving the corners all the way to the marina and up the hill to the Parking lot on Glacier Ridge. You‘re all warmed up! Bleed out some air and ride the trails back down.