“A doubletrack running through a forest growing out of black sands from a volcanic eruption 300 years ago.”
— Lost Justpastnowhere
This doubletrack is unremarkable except that it allows access to some of the more interesting terrain in the Montañas Negras (Black Mountains)
and Arenas Negras (Black Sands)
However, the price for admission is 300 m or 500 m (1000 ft or 1500 ft) of climbing, respectively. The climb is pretty steady at about 10% grade. About halfway up, you'll reach the Arenas Negras recreational area which has facilities including probably water if you need a break from the climb.
Most of the trail is through pine forest which offers some protection from the sun.
There is limited parking off of TF-375 at the start of the trail.