This can be done as a 2 day backpack with camping around mile 16.6 at the Manor Area Campground of Cunningham Falls State Park, reservations suggested. Cars cannot be left at the Gambrill SP Trail System Parking Area overnight. You can park at Gambrill State Park (call them) and take the Red access trail from there to the Trail System Parking Area. No camping is allowed along the Catoctin Trail. This hike will take you through 2 state parks, a Municipal Forest and a National Park. You will also cross many streams and hike by at least 4 beautiful ponds. Watch out for mountain bikers on much of the trail.