What about some new quests that send you to the popular levelling zones. Similar to ZenTex's suggestion for a quest that sends to Plaza 1. It would be good to have these as new jones quests that he hands out after the third one. If you're feeling ambitious, make a few different quests that lead to different levelling areas. Split them up by rank requirements and/or profession.

For example place a 'John Doe' at the end of an aggie cellar and the quest is to kill him, you'd have to get past all the mobs to reach him. A newbie's first instinct would be to fight the mobs, not run past them all. In the process they'll likely gain a few levels and disocver that it's a good levelling spot.

Finding out about these locations is like a priceless quest reward for a new player.