As a very casual highpointer, it didn't take much convincing to include a short detour to run Guadalupe Peak while on a road trip down to Big Bend National Park.
While no FKT was listed here previously, someone by the name of "Brad B" had the strava KOM time of 1:24:06 dating back to 2015. Some familiar names to trail runners like Nick Clark and Jason Schlarb have run the peak, but I don't think either one was giving a full gas effort.
The full ascent took 50:17, and could potentially be a separate FKT. Given how remote the park is, I'm sure not many people are able to return multiple times, so it would be nice to race up then simply enjoy the views while jogging down. Anyway...I didn't do that, but spent 1:16 on the summit taking pictures, then descended in just under 30 minutes. Given my usual clumsiness on rocky terrain, I was surprised I managed to keep the rubber side down and avoid any big crashes.
There's definitely some time to be had here by avoiding any downtime on the summit and being less risk averse/dealing with less traffic on the descent. So get after it if you're passing through the area!