Post Office Key Trade for $20 and 9 Acorns with Chip & Dale (Secret Challenge 1).

Print Shop Key Trade for $20 and 9 Acorns with Chip & Dale (Secret Challenge 2).

Garage Key Trade for $150 with Chip & Dale (Secret Challenge 3). You must also beat the following times:

21 Railroad Pennies Collected around the overworld.

18 Acorns Collected around the overworld.

15 Mickey Tokens Awarded for each non-boss race completed in 1st or 2nd place.

12 Vehicle Upgrades Buy from Ludwig von Drake. 3 each (Top Speed, Acceleration, Handling) for 4 vehicles. There are no upgrades for the Hovercar.

12 Print Shop Photos Silently awarded after winning every race or completing every minigame for a given character. Some photo requirements are currently unknown.

9 Magic Spells Buy from Magica de Spell.

9 Post Office Cheats Visit the Post Office with each character after reaching a currently unknown threshold of completion to receive a letter with 1 or 2 cheats.

6 Golden Bones Awarded for completing each of the 6 Pluto boss puzzles.

5 Vehicles You start with one. Buy 3 more from Ludwig von Drake. The Hovercar is unlocked by using the Garage Key on Mickey's garage.

5 Pluto Parcels Awarded for beating Pete in the boss race for each character.