Hey,
I'm not sure if this has been discovered yet but I found a way to get on top or outside AV. It works for both Horde and Ally. You may need an Epic mount to do this.
Find this area:
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Here is the location on the map:
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Next you want to make sure to be up as far as you can go. Make sure you are on your epic mount (Have yet to test a normal mount). Then Turn until you see this area:
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Next start running and unleash a mighty jump and try to land as close to the top of the cliff as possible. Make sure you keep running, then turn so that you are facing the ledge. If done correctly you will make it to solid ground.
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Next just turn left and run up the hill. You will see the outside of AV. You can actually get down there with a Parachute cloak, invul of some kind, or feather fall mage spell(may be more ways).
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Have fun!