Take I-70 to exit 218, just 3 miles east of the Eisenhower Tunnel. Exit I-70 and pull into the dirt trailhead on the north side of the interstate.
This route is fairly straightforward but above Herman Lake it requires a mile of off-trail, Class 2 hiking. Near the trailhead kiosk, start up the trail (Photo #1) and after 0.2 mile, turn left toward Herman Gulch/Lake - Photo #2. Follow the excellent trail into Herman Gulch where you’ll get several opportunities to view Pettingell along the way - Photo #3 and Photo #4. Near 11,900’ and after 3 miles of hiking, stay left at a trail junction - Photo #5. Continue a bit farther (Photo #6) to reach Herman Lake, at 12,000’. Leave the trail and walk north along the east shore to reach the north end of the lake.
Locate a prominent gully and ramp (Photo #7) used to access the south slopes of Pettingell and ascend the left side of the rocks in the gully - Photo #8. You’ll find a combination of grass and talus but the climb does not exceed a difficulty of Class 2. Once you reach easier ground near 12,500’ (Photo #9), continue west up broad “ramp” on grassy/rocky terrain - Photo #10. Keep hiking west to eventually see the saddle between Point 13,418’ (left) and Pettingell (right) - Photo #11. Ascend easy scree and talus to reach the saddle and turn right (north) to begin your climb of the summit ridge - Photo #12. After an easy 200’ of elevation gain, the summit pops into view - Photo #13 and Photo #14.