I follow Joana's guide but it's not that good for multiboxing because he skips a bunch of quests that are easy to do when multiboxing.

The real problem lies in that there are some collection quests that you really should do, even though they're a big drag - e.g. the ones in the shimmering flats - as they are the start of long quest chains. Joana's guide is overly focused on a solo speed run to 70 without exploring any content that's even slightly to the side - e.g. instances