I really was in the midst of putting together a quick video guide when the Deathcharger's Reins dropped for me last week. You, too, can have this ultra-rare mount in your possession if you're willing to embark on a relentless pursuit (or if you're just plain lucky). I don't know how many hundred times I've cleared this place in the last six years. Several hundred, for sure.
This four-and-a-half minute video offers a quick run-through of the dungeon along with some tips and tricks.
1. Enter through the Eastwall Gate in the Eastern Plaguelands.
2. You should be able to avoid aggroing all of the trash in here. If you aggro a mob, deal with it in place to avoid pulling additional trash.
3. You must kill the first three bosses and the acolytes inside the ziggurats behind the bosses in order to reach the Slaughterhouse where the final boss who drops the mount, Aurius Rivendare, is located.
4. BoEs in here have translated into thousands of gold worth of transmoggables for me since MoP---you may want to hold onto what drops and try selling it on the auction house.
5. Each run should take you 3-4 minutes once you get the hang of it; of course, you'll quickly hit your instance limit this way. However, the instance limit is per account, per realm. If you're up for a serious farming sesh with multiple characters, run it once with character 1, then immediately log off and onto character 2. Once character 2 runs it once, log off and back onto character 1. Character 1 will now be just inside the start of the instance, not in the final boss room where you left him/her. Take a few steps to port out, reset all instances, and port back in. Rinse and repeat.
Good luck, and thanks for reading/watching!
Looking for more soloing action? Check out my guides on Malygos (Azure & Blue Drakes) and Onyxia (Reins of Onyxia).