This is a must have addon for anyone who gathers herbs, ore, or treasure seekers. There is a nifty little addon for Cartographer called Routes. You can use this to track out a path to hit every item you are looking for in a zone. You can download Routes from the WoWAce site.
Once its downloaded and you restart WoW go to your Cartographer Options and look on the left side and you will see Routes. Click on add (which is highlighted yellow in pic). You will now be able to add info from the zone you are currently in. Title it something related to the zone and items you are looking for. Click on the drop down menu like in the pic and click on whatever items you want to look for. You can go back later and change this if you decide you dont want to search for certain items. Click on the drop down menu again to close it and click Okay.
Now you will see a menu like you see in the pic. Don't freak out about all the lines on your map. Go down to background and click Optimize. Doing this in the background will let you continue to play the game with only a little lag. You can do this in the foreground but it will lock up your computer for a little while so only do it if you are in a safe place. This will take anywhere from a couple seconds to a few minutes in the background depending on how many nodes you are mapping.
Once it is finished you will see a line connecting all the items you are looking for on both your large map and your minimap. Now all you need to do is follow the line on your minimap to check out what is closest to you. Remember this is going by shortest distance, not path of least resistance. In zones like BEM you will be going up and down the cliffs following the line so if you have a slow mount it would probably be faster to jump lines so you are searching the same area on a land mount instead of flying all over the place.