Well... I made it 27 miles out of the total of 50+. A combination of small things added up to be too much.
Main areas of poor planning were...
Failure to train on gravel/dirt surface. I was expecting mostly city rucking and therefore avoided too much "trail time". This was a huge mistake as a solid 30 miles of the 50 was on a pea gravel/dirt trail.
Failure to wear waterproof boots or socks. It rained Friday night all the way through Saturday morning. This lead to massive and often unavoidable puddles on the trail. Waterproof boots or socks would have greatly mitigated the damage done to my feet from the water. I got blisters and pains in places on my feet that I have never experienced before. I believe this was in large part due to spending basically 9 hours and 27 miles walking in completely saturated shoes/socks.
Likely not quite enough miles put in training up for the event. Ultimately it was the fact that my right leg basically locked up that led to me deciding to tap out. I believe this was likely due to a combination of walking funny because of blisters and not quite enough time spent under load in the months prior.
Overall a good learning experience, it's the furthest I have ever rucked/walked straight by a large margin.
Certainly a lesson in doing hard things, but still very disappointed in my self.
There's always next year...