Jim Walmsley crushed the R2R2R FKT on 10/4/2016, 5h55m20s! Walmsley set the R2R record on the way, despite going in the harder South-to-North direction (see above). Walmsley fulfilled Jones' 2011 sub-6-hours-within-5-years prediction just a month before the deadline! Trail Runner Magazine has a good first article on the run.
5h 55m 20s