Two observations if I might;
1. As has already been said, traveling rough, mountain country at night is just a plain bad idea. In survival school, it was always emphasized to wait until light.
2. You absolutely cannot trust the little off-road lines on Garmin. I tried to detour around a traffic tie up out of Laredo and rode about 40 miles of gravel only to find a locked gate and high fence across the road, which then led to another 40 miles of gravel and another hour or so getting around the traffic tie-up. All this at 108 degrees, but I did have water.