The Al Foster Trail is a long point-to-point trail passing through parts of Sherman Beach Park and Castlewood State Park. The path is mostly packed gravel and smooth dirt, but the trail does become muddier, rockier, rootier, and more overgrown once you get to the section within the state park. The trail runs along the Meramec River pretty much the entire time, which is a nice addition to a forest trail. There are a few different parking areas, so you can really start from wherever you want and do different out-and-backs depending on how far you want to go.