When approaching the turnoff from U.S. 395, the sign will say Bircham Flat Road. The sign for road 41 will then be seen once you turn off.
When crossing Desert Creek on foot along road 115, be prepared to get wet up to your shins, or you can find a nice place to hop across about 30 yards upstream
The road to Boulder flat is extremely rough and only suitable for trucks or jeeps. If any other sort of vehicle, I strongly suggest parking in the small plateau at 8500 feet, as described on the Wheeler Peak page. Even getting there might be a challenge depending on your vehicle.