The North Face of Mt Borah/Rock Creek approach map. The road from Highway 93 is shown in red and the Rock Creek hiking approach in black. In high water Rock Creek might be too high to get across safely so it is recommended that you stay on the right side of Rock Creek for the entire approach. Stay reasonably close to the creek until you are forced to go higher but don't go too high or you will end up on the cliffs. Be aware that there are two Rock Creeks on this mountain, one on the west and the other on the east. The western approach is the one most often used and is the shorter and easier drive of the two.
Birch Springs Road leads to the (dry) campground and start of the very popular southwest
(Chicken-Out) ridge trailhead. The southwest ridge is typically used as the descent route for north face climbs and is in my opinion the best place to park and start a north face trip. When starting from Birch Springs stay low and follow the contour near the old earthquake scarp line into the Rock Creek drainage instead of climbing over the ridge.