Well, if you haven't resubscribed your accounts already, you can make use of the new Scroll of Resurrection. This will let you insta-80 one toon per account. They will also get 80 gear, bags and a mount. Your accounts that are reactivated with SoR will also be upgraded to Cata for free. the new SoR also allows you to faction and server transfer for free, so if you wanted, you could use it to join The Zerg, which has several level 25 guilds under it, so you'd get bonus XP for leveling from the guild perks.


If not, XP has been revamped all the way up to the new content, so leveling is much faster. You'd probably boost or level through questing much faster than it would take for you to get full sets of heirlooms.