Where are all the locations that the Song of Discovery can be used in Legend of Zelda Spirit tracks i know adoba and bridge builder?

Answer 1

As you said, there are treasure chests in front of the two trees in Adoba Village, and in between the four boulders in The Bridge Builder's yard. There are also ones used in quests, like when you find the regal ring at Linbeck's. Another quest is at Disorentation Station. There is a hidden chest in the Black Ore mine. I do not know of any others, even though I think that there may be one at Crystal Springs, or where the train genuis lives.