I haven't done it in a while but there were 4 quests, one trick-or-treat in each city, and they'd give pretty good XP at level. Not sure if they've been implemented yet; all I've seen for sure was the candy you can buy that changes your form.
Solo: Frost mage vs murlocs. It's terribly boring but you can handle 40 levels of it. Or maybe 60 if you can somehow keep yourself entertained.
Other than that, if you have a high level dps friend nearby you can just grind elite areas (like underground in deadmines) by tagging the monster then having your friend finish it off. This is the best method for melee because you can land damage on higher level enemies in ways that a spell or wand can't.
I don't know anything about mangos or mob psychology or whatever, but I respect your accomplishment...
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... Eventhoughitdoesntcountbecauseyourealliance