How to get to GM Island in 4.0.6.
This method was founded by arrrdolf. I simply did it myself, added alot more tips and details based on personal experience, and uploaded to WCM.

Looks like Blizzard did interact with the area a little. The ground texture is gone.

Music was Paranoid Android by Radiohead

And some thought exploration would die! Hah! Oh, you... :)

PS- I don't play horde but I don't see why it wouldn't be possible as a horde player. You will have to improvise a little, but you'll need to have the same concept and mechanics from this video.

If you have any questions or if you're confused then feel free to contact me in-game or on WCM