This route is best explored by bicycle, though walking or jogging is an option. My favorite part is the crossing of Salmon Creek. There is some kind of work being done beneath the bridge, so steps have been built to walk down from the path to the area beneath the bridge. These steps are likely just temporary, to be used during the current work, but it gave me a convenient path to get down closer to Salmon Creek.
This is a multi-use path separated from SR 503, running alongside it from Brush Prairie to Battle Ground (about 2-1/2 miles). If you want to walk it, the best places to park and access the path would be on 154th St (at the end from the east side, so you need to go through Brush Prairie to access the dead end) or 179th St (park on 122nd Ave north of 179th St.).