Directions to Old Angler's Inn parking area: Take the Beltway exit 41 north towards Carderock, on the Clara Barton Parkway, and go north for 3 miles (go past Carderock park, and turn left on MacArthur Blvd). Park in the parking lot on the left, across the road from the Old Angler's Inn. Using this trailhead is free - if you drive to the Great Falls Visitor Center, you will have to pay the National Park admission fee. Two great routes to start: 1) walk north on the Berma Road carriage path and return on the towpath. 2) Hike the Billy Goat Trail section A 1 and return on the towpath. The Billy Goat trail has some challenging steep scrambles.