If you use ilvl640 epics that require level 91, you can go 91-100 really fast. Like under 6 hours. All you need is XP potions, and line up all the bonus objectives with the most treasures path. Also in spires of arack, there are 4x urns that give like 25% of a level in rested XP bar. Save that for 99-100. I'd do as many quests in Spire of Arack with the 20% xp outpost

1- 90 = dungeons if you can insta que
90 - 100 questing

How were the queue times?

I get a stack of movies to watch and then get my grind on while watching movies. There's no cheap or easy way out of 90-100 except for using http://www.wowdb.com/items/120182-excess-potion-of-accelerated-learning, but as someone already mentioned, you do need to get most of the quests done in order to upgrade your garry.

which urns are you talking about?

Pretty sure the urns are like 5% rested, not 25%. There are also items that give rested in SMV, although I'm not sure it is worth the trip at 99.

Im on my 3rd 100, got from 90 to 94 in 8 hours, but not rushing at all, following the quest line etc, randomly running dungeon.

IMO, if I was to rush or anyone, you could possibly get from 90 to 100 in a day (12 hours) easily.

This lol I got like one bar of rest from the urns