We walked this trail, including Bear Gulch Cave/Reservoir trails and it totalled 18.5kms. A beautiful day out. It took 6 hrs but we stopped for 30 minutes for lunch and 15 minutes watching Condors and several minutes chatting, so 5 hrs walking time say. This park is so different after Yosemite and Sequoia but still beautiful! We drank 2 litres each but it was November and 22C as a high. The tight narrow part was no problem for my wife, who hates steep drop offs. A very good trail with cut steps and hand rails.
Highly recommend.