Yeah, guides used to be somewhat necessary back in the day, but nowadays it's easier to level.
You can stay in one general area (such as Durotar -> Barrens -> Stonetalon Mountains -> Ashenvale for Horde or Elwynn Forest - > Westfall -> Redridge Mountains -> Duskwood for Alliance) and level just fine.
I think the guide (or whatever it is) you're using might be based on leveling back when it was considerably harder. Back then, it was pretty much necessary to go everywhere if you didn't just want to mindlessly kill random enemies in order to level. Now, not so much.