The issue was that strong headwinds, and rolling hills that looked like a straight decline on the elevation map, conspired to leave me out of daylight 20 miles away from Fort Davis. Even though I'd just recharged the headlight, this wasn't good, since there were cattleguards on the road (which force me to slow down even with the headlight on high). I swore up and down last time that I'd camp by the side of the road before I did another descent with cattleguards at night, and I meant it.
But as it turned out along the route was an astronomical observatory (the MacDonald Observatory run by University of Texas), and it turned out their visitor center was open late because they were hosting a late night "star party." So I got to use the restroom, refill my water bottles, tour the visitor center, and camp near the center. All for free, and now I'm looking up out of my sleeping bag at a night sky just as great as the last one.
This area is uninhabited other than the observatory, so no light pollution.
If I'm able to get a good enough start tomorrow, I'd like to make the 71 miles to Marathon, making my reservations for both Marathon and Sanderson while I'm in Fort Davis. While in Fort Davis I also plan to see the fort.
Although ultimately today turned out fine, I am not inclined to try mileage in the 90's again: at my pace, and during winter, it just doesn't leave enough margin for error.