This is a shared trail used by horseback riders and mountain bikers, but it is very nice. Start from the north end of the parking lot, follow the little arrow trail markers. You'll pass some old buildings and foundations which are remnants of the Fort Crowder days of WWII. After almost 7 miles, you'll finish on the south side of the parking area near the bathroom. The trail is rough and poorly marked with many fallen trees.
In Neosho at the junction of Business 71 and Highway 59/60, take 59/60 east to Oak Ridge Extension, then south to Burr Crossing Road, then east to Landis Road. Continue east on Landis to Doniphan Drive, then south to area parking lots.
More info can be found here