I have alot of alt..first I start at Maiev, have almost all class except DK.
Then transfer to Thaurissan. Only bring my main. I create another 4 alt there. Fastest way to ding is to equip heirlooms and queue as tank or heal. Anyway queue as tank will be much faster. If you are dps class only like rogue/mage/lock, set your heartstone to ogrimmar and check command board. If got quest to certain area for example Ashenvale , just go for it eventhough you think it was quite high for you.

My record for fastest ding to lvl 80 is 12 hours(play time) with my RAF friend. I queue as tank while he queue as healer. At lvl 70, i still have a few lvl 20 gear item.

Nah..raf bonus only till 80. No more after that..Im doing questing with my RAF only now.

nope..my friend..he from lowyat too.i dont think so you can raf another cata account. Recruit a friend feature only work on new i account i think.