I think you are underestimating the difficulty of this. It's not 78 miles in 30 hours. It's 3 full marathons of certain given paces. You don't get to stop and run it in separate sessions. Really, only the very best runners could do this- approaching elite level.
Nowhere near elite level, the fastest pace is outside 7.30min miling. That is over 30 seconds per mile slower than the 100 mile record, only 3/4 of the distance, spread over 3 efforts, and with the first 2 marathons at an even slower pace. This isn't some tricky trail race.