Inner Basin Of The San Francisco Peaks - Fall Colors In The Inner Basin, September 23, 2016. The Inner Basin Trail Ascends From Lockett Meadow Into The Caldera Of The San Francisco Peaks, An Extinct Volcano And Home Of The Tallest Peaks In Arizona. The First 1.7 Miles Of The Trail Winds Through The Extensive Aspen Forest Flanking The Upper Reaches Of The Peaks, Joining The Waterline Trail Briefly Before Following A Jeep Road Into The Caldera. The Trail Starts At An Elevation Of 8665 Feet, Gaining Approximately 1200 Feet Over 2 Miles On Its Way Into The Inner Basin. The Trail Continues Another 2 Miles, Gaining An Additional 600 Feet Or So To Join Up With The Weatherford Trail. Photo By George Jozens, September 23, 2016. Source: U.S. Forest Service, Coconino National Forest. See Lockett Meadow Campground And Inner Basin No. 29 For Information About This Area Of The Peaks On The Coconino National Forest Website. Photo