As an ally, I really hate running into SM for the Headless Horseman event due to the incredible amount of horde who camp the area. So in my frustration, I tried to find another way around Scarlet Monastery. Much to my surprise, I found a way to get on top of SM, as well as underneath/inside it. I also found a large, flat area northeast of SM inside the mountains.
I searched for a very long time to anything relating to this area, and found nothing. If it is a repost, I am very sorry and will happily see this post deleted immediately.
(Warning: Several pictures incoming. Just want to be as clear as possible.)
The area you are aiming for is the far northeast of Tirisfal Glades. Here's the general path
Now you want to get to the top of these hills. I will outline the path I took, though there may be an easier way.
If you follow the mountains along towards SM, you can find one cliff that makes the roof accessible. You want to aim for the flat area at the top of the roof.
Once you're on the roof, you can follow it towards the front, and with some rocketboots/parachute work, you can manage to get up on the tower at the front.
However, the more interesting thing i noticed is in this picture.
You can actually go under this section of the roof (or the section on the opposite side) and get underneath SM. If you attempt to pass through any of the walls around you, you'll appear outside like normal. You can actually go to the front of SM towards the stairs, and appear inside of them.
Believe it or not I actually achieved my goal of finding another way into SM.
However, I went back to look at the path again, and I found a massive, empty area to the north.
When you fall down into this zone (I used a parachute, but you might be able to find a safer way down) you enter "Quel'thalas".
This is a huge, undeveloped zone that stretches all the way to the ghostlands in the east. Here are several interesting this I saw in the area.
Near the end of the trek, I jumped into a deep pit behind EPL. It is a very large area with massive walls and spikes.
The coolest thing I found back there was that you can see Stratholme.
I got as close as I could and found that you can see both instance portals, and the lake in front.
Once I jumped in here I was unable to get back out, and I'm going to continue to see if there's any way to go farther east than that.
I looked up as many keywords as I could think of in search, so like i said, if this is a repost, I will gladly delete this. Please kindly let me know if it is.