How can I get around Agartha more quickly? Are there any shortcuts?

Due to the nature of the way the Agartha is designed, with lots of branches leading off in different directions in combination with the lack of falling damage in The Secret World, it is possible to simply 'fall' to the branch you want.

Start in both cases with your back to the three main city portals (London, New York, Seoul):

Portals to Egypt:

• go to your immediate right (near the New York portal), to the edge of the platform,

• look down - below you will see the Egypt branch,

• jump down.

Portals to Transylvania:

• go to your immediate left (near the Seoul portal), to the edge of the platform,

• look down and place yourself so that you can fall down onto the branch below,

• run a few meters up the branch until the point where it starts sloping down again,

• look over the edge on your left side - you should now see the Transylvania branch below,

• jump down.

While looking for some screenshots to attach to save myself from having to wait for the game to update, I found this video which should explain it further: