Now that I've made actual attempts at overcoming some RL limitations on my PvE team's Northrend leveling, here's the scoop so far.

My PvE team was grinding instances to 70. I had nearly every quest from Terrokar Forrest and up to do after hitting 70. Why? Easy gold. Anyhow, I hit Northrend just after dinging 72. Yeah. So I'm FINALLY playing regularly again and have just leveled to 75 without entering any instances, but doing EVERY quest I can get my hands on. I've not quite finished Borean Tundra, but I have completely wiped out Howling Fjord.

First and foremost, I'm learning to love collection quests. Yeah, there's a definite slow-down factor when doing them, but they're almost totally indispensable for several reasons. I'm likely going to be half-way to 76 before leaving the "starting" areas. Dragonblight follows and then on to Grizzly Hills. From there, we'll see. I've read a number of reports that are forcing me to save for the level 77 cold weather flying purchase. That has been done already on each of these characters. After that, it seems like the epic flying will come quickly enough if I keep up with the questing.

I think my situation (what with starting Northrend at 72 and all) is pretty unique and will probably not help anyone, but I thought I'd share a different perspective.