Ok kids hold onto ya arseholes because a massive shortcut has been found in Wuhu Mountain Loop or Maku Wuhu as I’ve seen it called in silly countries. To activate it and skip almost the entire second section of the course, take a hard right off the track and into the river immediately before entering the cave. You should aim for the far wall. if done correctly Lakitu will place you on a later part of the track making times faster than 1:20 easily possible for the course.
Worryingly, I’ve verified that it’s possible to do without a mushroom, making it readily exploitable for online races.