Rishel Peak has no trailhead and no trails to its summit. This route is probably the most feasible given road access, but other routes would likely be of similar character and difficulty.
From anywhere in the universe, find exit #4 on Interstate 80 in Utah's west desert near the Nevada border, also the exit for the Bonneville Speedway. From the exit, travel north and follow signs for Leppy Pass. From Leppy Pass, take the first right turn onto the dirt Silver Island Mountains Backcountry Scenic Byway. From the turn onto dirt, travel 3.3 miles. This is the trailhead for two wheel drive vehicles. Park off the road.
4WD or higher clearance 2WD vehicles can follow the double track road to the east for another mile or so.
From wherever you parked, follow the doubletrack road until it crosses a wash that leads to the north ridge of Rishel. Follow this wash to a small saddle on the north ridge. Gain the north ridge and follow it to the summit. The ridge involves Class 2 and Class 3 off trail hiking and scrambling. The summit ridge is narrow and sees few visitors. Take care to travel in the open desert in the washes to avoid trampling the vegetation.
Route Stats (from the main road):
4.4 miles round trip
1430 feet elevation gain
Sun protection and water are essential. This mountain has no shade and no water sources whatsoever.