This was an easy 2 mile round trip hike through a creek bed. The turn off to this can be easily missed. Theres no signs. The turn off to the mule canyon trailhead is just before the mule canyon ruins on the north side of the road. There’s a fee area shortly after you drive down the dirt road. It’s $5/vehicle. Drive another .25 miles and park along the dirt road. Down to the left (in the creek bed) is a sign-in station. From here the ruins are one mile (one way) along the creek bed. It’s a great hike for kids.
This was one of our favorite places to visit in Yellowstone. There are a few RV parking spots available here. Show up early or during dinner hour as it fills up quickly.
We arrived on 10/19/18 and didn’t have to pay a fee. The bathhouses were closed and no life guards on duty. It was 61 outside and we still went down the rock and it was so much fun. The rocks are very slippery. Wear water shoes. Bring a towel and go sliding!