I used to run out of quests in Hellfire, and need to run Ramparts/Furnace once each, to reach 62nd.
My four-shammy team was almost 63 when I left Hellfire.

I'm into 67 already, and have not finished the Terrokar quests.

My progression is the same, following the Brian Kopp alliance quest guide.
So... Hellfire - Zangamarsh - Terrokar - Nagrand - Blade's Edge Mountains - Netherstorm - Shadowmoon Valley.

As a bonus, the quest stacking guide is efficient completion of the quests he choose to do.
Which means efficient stacking of an awful lot of gold-farming, once the leveling is done.