Parking costs $2. Grab a ticket on your way into the park, then head to park office to pay and they will validate your ticket. Keep the ticket, you'll slip it into the machine to exit the park.
This is only a 0.75 mile singletrack trail but proves as a nice increase to the distance of your outing and to link the other trails in Waller Mill Park. The trail is mostly smooth and compact with little to no elevation change.