On Highway 9, 1 mile south of Alma, turn west onto Mosquito Gulch Road. Drive 6.8 miles to a point where the road turns left and crosses Mosquito Creek before climbing up toward Mosquito Pass. There’s parking 0.1 mile after the left turn.
This is an "unofficial" trailhead but includes parking and a good place to park if you have a 2WD vehicle. From your parking spot, walk to the junction of the Mosquito Pass road and the 4WD road which heads northwest toward the upper end of Mosquito Gulch - Photo #1. Hike up the 4WD road (Photo #2) for 0.5 mile to reach another road junction - Photo #3. Turn right and switchback east up a narrow 4WD road which goes to a mine in the upper basin.
Near 12,100’, the view opens up and the road continues north toward the upper end of the basin - Photo #4. Continue (Photo #5) another mile to reach mine ruins at 12,600’ - Photo #6. Turn left and continue west toward a broad saddle above the northwest end of the basin - Photo #7, Photo #8 and Photo #9. Near 13,100’, and before reaching the bump on the ridge shown in Photo #9, angle right (Photo #10) and ascend rocky terrain to gain the base of Tweto’s southwest ridge - Photo #11, Photo #12 and Photo #13.
Now near 13,300’, turn right and follow the ridge northeast toward the summit - Photo #14 and Photo #15. Stay near the ridge crest and ascend sometimes-loose talus (Photo #16 and Photo #17) to reach the summit. Photo #18 looks northeast to 14ers Quandary Peak, Mt. Democrat, Mt. Cameron and Mt. Bross.