Tunnel cut into the steep base of San Gabriel Peak and completed in 1942 by the USFS.
- Eaton Saddle to Mt. Lowe: 3.2 miles, 520′ gain and loss.
- Eaton Saddle to Mt. Markham: 3.2 miles, 790′ gain and loss
- Eaton Saddle to San Gabriel Peak: 3.2 miles, 1071′ gain and loss
- San Gabriel Peak Trailhead to San Gabriel Peak to Eaton Saddle: 3.4 miles, 1,411′ gain, 1071′ loss
- Eaton Saddle to Mt. Lowe, Inspiration Point, Mt. Muir, and Mt. Markham: 8.8 miles, 2211′ gain and loss.
- Red Box to Valley Forge, Mt. Lowe, and San Gabriel Peak: 11.1 miles, 3,020′ of gain and loss.