We leveled a shaman, a warlock, and a mage to 57 in equal played time to this mage. The played time seen here includes two hours of AFK time and about an hour of travel time. We wasted about an hour going to BRD to attempt to get better exp there between Scarlet Monastery and Stratholme. Under optimal conditions (but without rested exp) one should be able to reach level 60 in about 1 day 15 hours using PsiVen's method.

1-8 Regular leveling.
8-15 RFC.
15-24? SFK.
24?-27 RFK.
27-30 RFD.
30-45 SM.
45-60 (for us, 57) Stratholme.

We used a paladin in full Holy season 2 PvP gear, specced 9/39/13, and it got the job done well. A few things to note:

We stopped at 57 because the paladin's account expired, otherwise we would have gotten level 60 in under 2 days played.

* Full clear RFC, rank 1 consecrate is enough to kill everything while you run as fast as you can.
* Full clear SFK, again don't stop for anything. If you hit the cap, immediately go outside and do a clear of Pyrewood village, then come back and by this time the cap should be up.
* RFK through RFD was a boredom choice for us and quite possibly not optimal since the travel time to go from Silverpine Forest all the way to the southern Barrens is substantial. Your call.
* RFK full clear.
* RFD only undead side. The quilboar side will often have reset back to their spawn points, making life difficult for your alts.
* For SM, we utilized only cathedral and armory as early as we could. I pulled the entirety of armory at once, bubbled, healed up, and we aoe'd it down. For cathedral, since the paladin had no tank gear I pulled it in two separate groups (one group for both the courtyards and the other for the cathedral).
* For Stratholme, kill the undead aoe packs only and reset. As a side note, with the retribution talent and some luck you can enter the back door and use exorcism on the Magistrate before he runs off, but you can use swiftness potions just to be safe. His key to Stratholme is helpful to have.