From what I remember of Wrath on launch, practically that meant Borean and a little bit of Howling or Howling and a little bit of Borean - then you had to do enough Grizzly Hills to do Zul'Drak and you either did a couple of dungeons or started on Icecrown after Storm Peaks. It would have worked better if you could skip zones entirely, but it didn't work out like that in practice.