This gravel forest road FR 42 is the eastern part of the connection from the town of Portal at Cave Creek Canyon up and over the mountains before dropping down to Hwy 181 near the West entrance to Chiricahua National Monument. It connects to the paved end near Portal, labelled Cave Creek Road, while the section west of Onion Saddle is often labelled Pinery Canyon Road or South Pinery Canyon Road.
The first four miles on Cave Creek Road from Portal are paved. Just before the Southwest Research Station at Herb Martyr Road (FR 42A) it turns to dirt and is a graded dirt road the rest of the way. It is rocky in places. In Cave Creek Canyon camping is only allowed in campgrounds. Once you are on National Forest land beyond the SW Research Station there are tons of dispersed camping sites all the way to the forest boundary.