For me it was- start quest, talk to Mithra next to quest starter, go to San d'Oria, get on stage, head BACK to Mithra for clue, then I went through the maw at Battalia to the past, entered Jugner Forest [S], stealthed my way to the lake, and you just follow the shoreline until you find the stones to snag a stardust pebble, get the cutscene, head back to Upper Jeuno (I just used a warp scroll), done.

Obviously now that you're a DNC 32, you managed...but that's for anyone else doing the Dancer Job quest.