Outland you can pick and choose a little,myself I do most of the Q zones,just so I finish on 68+ halfway through Nagrand.
In Northrend there is not easy way around it unless you are mainly instance running on rested XP,I quest using Idemise guide as normal giving me important faction rep as I go.
Grinding every zone q in Northrend helps leave zones untapped when you ding 80,getting you heaps of gold for your Epic mount or PL professions.
Also there are some rewards for maxing all Q lines such as Loremaster of Northrend,which unlocks the Tailoring pattern Deathchill cloak.
This is what I have done,i'd also add that you might want to consider doing some death knight,or paladin before your ice mages as you will need a strong tank if you ultimately start on Heroics.
Hope this helps and GL with your q'ing