There's already a One-Way and Out-and-Back FKT for the 37.1 miles of the BRT from Boxley - Pruitt. This challenge was slightly different for the BRT, so I tried to submit a new route. I did this solo and unsupported at moderate (perfect) water-level in a 13.5' Necky kayak. With the BRT paralleling one of the best rivers in the country, it made a lot of sense to combine an ultra-paddle with an ultra-run. The paddle section is ~24 miles and the run is ~29 miles, so it meets FKT guidelines and creates a full loop. This "Ponca - Pruitt loop" is one of the most heralded, iconic river sections in the country. Boxley was cut out because the river conditions fluctuate, are different for that section, and are not typically safe for solo-paddling. I did this in just over 12 hours in daylight. It was amazing! I carried my shoes, clothes, and food in my kayak. I did not filter water and instead drank from fresh streams. Running east to west had some big elevation gains, but 80% of the trail was runnable. I was unable to locate any record of others doing this loop, but this is the kind of Bucket-list adventure that people need to (WILL) do more of in the future out there. This ranked up there with some of my bigger single-day adventures like Grand Canyon R2R2R, 4 Pass Loop, Grand Teton, and Mt. Hood.