I can't seem to find how to get to that island south of the red south mushroom area (the red map). I heard that is a good place to go at 52, but its kinda hard to go there without seeing a way to get there XD.
I had heard there was a turtle on a beach some where, and I found one near a boating dock area, did his quests but I was not transported anywhere, he just stopped giving me quests after a few runs back and forth from a tiny buu NPC.