Crap. Voted before I saw the "PL with 70 mage" thing.

With a 70 to PL you (especially AoE classes) instance bombing runs are the fastest and best in terms of money from loot.

Without a 70, straight questing is the fastest way to solo/duo/trio to 70.

With a 4-/5-box group, quest until it's instance time then run the instances at your level or just when the lowest quest starts turning green to you.

With the changes to the 20-60 XP rates, questing positively FLIES through the levels, even multiboxing AND doing the collection quests.