This past October I drove Pinto Basin Road and Cottonwood Springs Road on my way out of Joshua Tree National Park. Both routes act as a singular roadway which connect Park Boulevard in the Mojave Desert south 37 miles to I-10/Box Canyon Road in the Sonoran Desert by way of; Wilson Canyon, Pinto Basin, and the Cottonwood Mountains. Interestingly both Cottonwood Springs Road and Pinto Basin Road have an interesting backstory as part of the highway from Shavers Well in the Sonoran Desert north to the mines of Old Dale and New Dale near Dale Lake of the Mojave Desert. The connecting route to Park Boulevard appears to been built within the eight intervening years between Joshua Tree National Monument being declared in 1936 and 1944. Either way the route of Pinto Basin Road/Cottonwood Springs Road is interesting in that it connects two deserts.
https://www.gribblenation.org/2019/12/pinto-basin-road-and-cottonwood-springs.html
I drove that road twice this past summer from the 29 Palms entrance of Joshua Tree to the I-10 because I wanted to see the Milky Way with my own eyes. Cottonwood springs Rd right before the I-10 is one of the darkest spots and you can really see the night sky out there. Had no idea about it's history. Thanks for sharing.