How to fast train high level pokemon in Black/White?

Please, NO AUDINO TRICK. Audino trick does not work for higher levels, it will take hours to get your high leveled pokemon (70-100) and thats if your using a traded pokemon with boost exp. I've been trying to train my primeape, and it's taking literally, forever. I've been working on it for 3 days so far and it's only level 72. Im also only getting 1k exp on my traded vaporeon from audino now -.- (vaporeon is now lvl 90) I appreciate if you could help. you might mention the elite four rematches but they aren't giving the appreciated experience I'm looking for. They give like 2-3k per pokemon, which is a slow rate.