Both starting areas?

[nydas]

Though you say doing Hyjal and then Vash is the quickest route to 85, have you taken into consideration the competition for quest mobs/items?

When I leveled on Beta, I did only Vash and was still able to hit 85 with quite a bit of Twilight Highlands remaining.

Did the 40% exp increase make doing both starting areas mandatory?

[Zygor Admin]

The Cataclysm zones tend to start from a postboard in the major cities (like Stormwind). You could complete one of the starting areas and then skip ahead in the guide until it says to accept "Hero's Call: Deepholm!" and continue there. Whether it would be a good idea to do this depends on many factors, including how the exp increase factors into things. Perhaps Zygor can chime in later and give a more complete answer.

[nydas]

Also need to mention that I'll be leveling in a full group, in case that changes the variables.