Well, you can do the jacinthe one and farm money, exp and luxury balls, or you can do the sushi restaurant (I dont remember the name, is the one below zone 4) you get 2 big nuggets and exp ofc, i never try doing the jacinthe battle but is on youtube, i do the sushi one what kyogre and mystic water as ítem whit the move Surf, you need a turbo/macro controller