I walked the Bigurda Trail, which is a 8km hike, starting at the Natural Bridge and going to the Eagle Gorge. I walk fairly fast, and it only took me a bit over 90 minutes, but most people should allow 2-3 hours. I had a vehicle pick me up at the end.
Most of the trail is just rough gravel, and you'll need sun protection and water. Most of it is right on the edge of the cliff-top, and views are spectacular. Highly recommended!