This route was pretty hard to navigate. A couple of times the gpx took me onto private property and I had to turn back due to a fence blocking my way. If you stick with your instinct and not concentrate on following the gpx exactly, then you should be ok (so, if the gpx takes you off the path, stick to the path instead). It was a very nice run with varied scenery and terrain. Not too muddy for a winter run but I still returned with muddy shoes and cut legs from the brambles! Saw belted galloway cattle and little lambs. Nice and quiet on a weekday. Personally, I thought my performance was poor, I wasn't there mentally - usually, I have a huge smile on my face when hitting the trails but today I kept thinking "am I nearly finished". I don't think it helped to have to stop every 100m to navigate, it was hard to get going again. It was the first time I've done this route so that was somewhat expected. I would definitely recommend it but you may want to do a reccy before attempting an FKT.
4h 10m 39s