Last night, when I got tired of killing zombies, I decided to explore a little bit. So I flitted around Agartha for a bit, and ducked into the parts of Egypt and Transylvania I have access to. Very keen. There are some hair-raising trips in Agartha, btw, plummeting straight down, or swooping up in a huge arc. Found a few pieces of Agartha lore.
Also, I got hopelessly lost in Agartha after awhile, so I decided to see what would happen if you jumped over the side. You immediately pop back at the main entrance.
Also, you can just walk normally between nodes if you go around the portal.
In speaking to the porter at the entrance, he mentioned that the older parts of the tree traveled to different times and other places. I wouldn't be surprised if that's in the works--you can see that this game is built to expand in almost every feature.
I'm ditching SWTOR, think I may pay for a lifetime subscription to The Secret World, I'm enjoying it so much. I see myself playing it in the long term, definitely.
Now to find a cabal.