Add these lines to your motogp.cfg file using notepad, and the whole thing is unlocked, including the mini-games. Also included is a variable to adjust your turbo-power, if thats your thing.

game/unlock_tracks = true

game/unlock_all_riders = true

debugcheat/lullbullbydub = true

debugcheat/freecredits = true

debugcheat/fake_all_challenges_complete = true

debugcheat/minigames_unlocked = true

cheats/turbo_amount = 1.3329999 (between 1.0 and 5.0)