UK is only worth it if you are rested. Otherwise go to Nagrand and do the whole nessingwary chain and the ring of blood quests. That should get you to 66 pretty quick. Then do the non collection quests in blade's edge mountains til 67 where you can do smv and netherstorm. I would go straight to northrend at level 68. The quests there give about twice the xp and you will get good gear upgrades.