When visiting Winterset City Park, I recommend starting with a drive through the park to Clark Tower, which is a one-way road with scenic views. The road to the tower is open from approximately April 1st through November 15th. Alternative, you can hike on the road which is a 2.3 mile loop.
Clark Tower is 25-feet high and was built in 1926. A winding staircase leads to the middle level and a steep metal ladder leads to the top level. The view from the top is worth the climb.