Too many things get done in this part, which is why it is so long and I don't put where I go or what I do in the title. So instead, here is a list of what I did:
-Enter the Rosemary's Haunted House to get the fourth melody.
-Get a bit lost in the Desert (this always seems to happen to me whenever I play this game)
-Find the fifth melody in the most random spot you could possibly imagine (Use Course A on the plane to get a subtle hint as to where the melody is. The plane circles around the cactus)
-Ride a tank for the best price you could possibly imagine, and this time I don't get lost in it.
-Destroy a giant robot called R-7037, who was sent by Giygas to stop us, using said tank.