From Las Vegas take HWY 95 north. When you get to Exit 93 set your odometer to zero.
At 2.5 miles you will drive by the turnoff for Mt. Charleston. Keep going straight.
At 16.5 miles you will see the sign for Corn Creek Road. Start slowing down and get ready to make a right turn.
At 16.7 miles turn right at the turn off for Corn Creek Road.
At 17.5 miles is the DNWR visitor center. Park here and sign the sign in sheet. This helps the DNWR get more money.
At 17.6 miles is the sign with all the roads. Make a right turn onto Mormon Road. Follow Mormon Road for 4.1 miles (22.0 miles total) to Gass Peak Road and make a right.
Drive 2.6 miles (for a total of 24.6) There is a little road to pull into on the right. Park here. This is the trailhead.
The trailhead is located at 36° 25.257N 115° 14.887W. The elevation is ~3,818.
From here just start walking across the desert straight to the peak. If you have a GPS put these coordinates of the summit in your GPS so you can track your progress (36° 23.297N 115° 14.739W). If you don't have a GPS just look straight South and start hiking towards the highest point on the East side of Castle Rock.
Once you get to the base of the mountain it is only about 350-400 feet elevation gain.
It is approximately 1.6 miles to the summit from the trailhead.
Once you get up to the top look for 2 cairns on the summit. There is a false summit west of the true summit. If you find yourself on this false summit look west toward Gass Peak and you'll see the two cairns about 100 yards or so to the East. Great views of Las Vegas, the Spring Mountains, and much more can be enjoyed from here.