Thankfully those last zones are pretty unnecessary now. You can probably get out, assuming you do at least a few instances per level, with only doing Hellfire, Zangarmarsh, the Terrokar stuff around the instances and maybe a bit of Nagrand.
As I've said before in this thread, my paladin ONLY did Hellfire and then was on his way to Northrend--and it didn't take long at all, especially since I was running those dungeons like a slave-driver as a tank with instant queues. Paladins are just super powerful though. You can carry nearly any ragtag group through <80 dungeons with your insane aoe threat, decently good damage, your Word of Glory crits and bubbles, and a nice selection of 'oh shit' buttons.
We'll see how it is with the shaman, since I'll be healing, and Outland is notorious for fresh DK tanks who still don't know their abilities (through not entirely the fault of themselves).