I finally got off my arse and levelled Kronas from 61 to 62 last night. I only had 1/2 - 2/3 of the level to complete and was fully rested.

It took me a total of 4 hours to level up - that’s 8 hours of non-rested time (or thereabouts). All the quests I did were situated in Hellfire Penisula, mostly around level 63.

Once I’d dinged, I completed the quests I was on and hearthed back to Shattrath City where I ported to Stormwind. Picked up the level 62 talents, and upgraded my legs and shoulders armour.

So it’s around 16 hours playtime from 61 - 62 (probably a bit high), meaning it may be something similar from 62 - 63.

Nice thing is, I made about 50G in the process. Well back to the questing.