This was a birthday run through my favorite trail system, starting at 6am (huge thanks to my wife for dropping me off) and ending just before 1pm (huge thanks to my parents for picking me up).
I ran with two watches, a 2016 Garmin Forerunner 230 and a 2023 Coros Apex 2 purchased to help me navigate this tricky route. The Garmin had me at 6:53:53 and 30.85mi. The Coros clocked me at 6:54:01 (since it's more fiddly to stop the run) and 31.45mi. From comparing my live track on the watch face with the gpx file I was following, it looks to me like the satellite on the Coros was much less accurate than the Garmin
It was nice and cool at the start but heated up significantly over the day. Current temps are high 70s and sunny. Fortunately the route is almost entirely shaded, which explains the bad GPS tracking. I struggled some with cramping and was grateful for the two salt tabs I brought along (and don't ordinarily take). I carried 500ml of electrolye mix, 3L of water, and a water filter. I drank the electroyle mix and 2 1/3 L. In addition, I took on board somewhere between 200 and 300 kcal an hour: one gu roctane and the rest various spring energy gels.
I managed to scout out about 2/3rds of the route beforehand over the course of four training runs, which helped enormously. In training I made some big navigational errors. Today I had to turn around a couple times but only after a few meters gone astray. The Coros watch (which I got two weeks and hadn't really run with on the course) was a game changer, though for a couple of the most confusing sections, I also consulted the gaia gps app on my phone.
Patrick's gpx file is spot on except for a few sections of obvious satellite error (where he appears to bushwack) and one recent very-well marked trail closure (on Gray's Mill Trail just past Thistle). The reroute adds a small detour, nothing significant.
Note there is one major discrepancy between Patrick's gpx for the one-way traverse and the cycling Patapsco traverse maps: the cycling maps miss out the college trail loop near CCBC. I took the college trail because that's a nice segment and the longer of the two options.