go to the north-east of the highwaste crystal, and give the chocobo greens.
go south two areas and go to the dead end. there is a chocobo path.
go through it and then go east, to the ledge, above the crystal.
push the big rock. this makes a passage to the crystal.
activate the spring to move the floatweed.
go up the mountain, to the summit, and you will find exodus.