i just power lvl my druid 32-60 using instances. When i was doing my power lvling i just made sure that my toons dots on the mini map where still showing and i was getting xp (i am a worry wort so i always have them close).

It depends on your money situation and how fast to lvl them. I had a lvl 32 that i wanted to be 80 (read 60-80 best questing) and found it a lot easier to just buy 1 more account (original $20) and link it to the lvl 32 toon. I then created 2 new toons and at 32 i switched in my other toon. At 59 i made sure my "friend" toon dinged first (1 bar from 60 on other toon, just to be safe) and granted him a lvl so now he was 1 bar away from 61 and just doing the welcome to outland quest i was 61. It took me about 3 days to do, but was looting when i did ZF and Start for cloth. Then i granted my other 32 to lvl 60.