There is very limited choice as far as quest progression.

We do one of Hyjal/Vashj'ir.
Then we can do the other, or Deepholm.

We basically get the choice of advancing to the current zone (having skipped one zone)...
Or in doing both starting zones, and being free to skip a different zone.

My first team to 85th (with basically no rested), has done five or six quests in Twilight Highlands.
With rested, they would have been 85th still in Uldum.



Well, can also do instances or battlegrounds or mining/herbalism for experience too.