From Fairplay, (watch for speed traps) drive north on State highway 9 to a left (west) turn onto County Road 12. If coming from Breckenridge, drive south on State highway 9 across Hoosier Pass to Alma (watch for speed traps) and turn west onto either CR10 (which joins CR12 after a couple miles) or drive another mile south and turn west directly onto CR12. CR10 is passable for any passenger car, but is much slower, bumpier, and harder to find than CR12. The graded, gravel road up to the provided coordinates is suitable for passenger cars and can be driven all the way to where it crosses Mosquito Creek as the road begins a large turn to the south. If in a 2WD, low clearance vehicle, park in this vicinity and begin walking. There are several pullouts along this section. Beyond the creek crossing, the road becomes a rough, rocky 4WD trail; high clearance, 4WD required.
NOTE: If you're unfamiliar with Mosquito Pass, the road can be driven in many stock SUVs equipped with 4x4 & higher clearance. However, the road is continuously rocky and does present some degree of clearance challenges for stock SUVs. It's the type of road that will put a fair amount of stress on your vehicle's joints & seals. If you're undecided, immediately after the indicated TH coordinates is a long, steep climb as the road winds south which will give you an idea of the road condition above this point. Snow will likely block passage on this side of the pass higher up on the 4x4 road later into the summer than on the west (Leadville) side—often until July 4th or later.
Some limited, primitive sites can be found along CR12, but watch for and respect Private Property signs. The nearest Forest Service designated campgrounds are located on CR18, which leads to the main trailhead for Mt. Sherman. CR18 can be located about a mile and a half south of the Fairplay US285/SH 9 junction on US 285.