Ive tried a few, but i find them hard to follow as a multiboxer - I generally look at them to show me what zones to go to and when, then use questhelper to do all the quests i can find (except collections). The ingame leveling guides arent great, majority of them have alot of grinding, My favourite is Brian Kopp's guide - it comes in both PDF guide and ingame guide although i havent tried the ingame guide for it yet.

Jame's guide is also good, wow-pro.com and its free - Ive never bought a WoW guide i only download them from where i will not say Not going to spend my money on something i might not even find usefull.