I decided to finally roll my Death Knight last night. I went through all the starting quests and then quested for a while in Western Plaguelands and Eastern Plaguelands, just for the sake of it and to get a jump on levelling in Outland.
I guess it was also helpful to kill lower level monsters and get a good rotation going, as well as getting more used to the Death Knight dynamic again, too.
I will now level his Inscription and Herbalism for a bit before hitting Outland and getting him to 68 as fast as I can.
Gaiwyn of Proudmoore