A Distant Shore

Fix Willy's boat to reach Ginger Island. The quest opens via a letter from Willy once the Community Centre (or Joja equivalent) is done - visit his back room, then supply 200 Hardwood, 5 Battery Packs and 5 Iridium Bars. The iridium is the gate: Skull Cavern runs or the Statue of Perfection cover it. Land on the island and this pops - and the whole late game (walnuts, Qi, 818922349, the last fish and recipes) opens up with it.