If you start at 68th in Howling Fjord or Borean Tundra, and do most of the quests in the first zone, then most of the quests in the second zone, you end up being well into 72nd.

You can supplement this with daily quests, which you can repeat quite often to get a little further ahead. And with battlegrounds, especially on a weekend for that BG. And instances, if you have the right composition; even if you cannot clear it, you can do trash or whatever.

With two zones for each leveling bracket, you could level entirely with questing without issues.