Instructions
Find Donald near the Emporium in Bog Easy. Speak with him to begin the "Find Donald's Parts" quest, then go to the gate leading to Lonesome Manor. Talk to the ghost to receive the "Play the Pipe Organ" quest, then head through the gate.
Go to the Lobby in the Library Area. Turn toward the entrance and locate the cartoon wall by the bookshelves. Apply the paint thinner to reveal a secret room. Enter to find Donald's left leg in a chest.
Move to the ballroom and locate the balcony by the organ pipes. Hop up to the balcony and proceed to the gap. Jump over to find a chest containing Donald's arm.
Head up to the Mad Doctor's Attic. Search the area around the trolley tracks to find a large trunk. Paint the trunk and jump on top. Look up to see a trolley track suspended from above. Jump up to the track, then to the pipes, and then to the rafters. Move across the rafters to reach Donald's right leg inside a chest.
Go to the ballroom and approach the organ. Stand on the platform here and agree to help. Hop on the keys in the corresponding order to play the song successfully. Return to Bog Easy to receive Donald's torso. Speak with Donald again to reassemble him and finish the quest.