Question about quest "Hole of Istan"

I am playing Nightfall and have all three campaigns plus the expansion, and I am wondering if I complete the quest "Hole of Istan" can I get back to Nightfall. I haven't even been able to travel between continents yet and would hate to get stuck in the Eye of the North when I have come so far with my character, but still have so much left to explore. I am sorry if this answer is here somewhere, but I have been searching for over an hour and haven't found one yet.

Any help would be much appreciated.

Thanks!

Yes you can.. ...........

when you get to tyria, you can click on the ship near Lion's Arch and then from the menu pick Kamadan or Kaineng centre or the Great Temple of Balthazar. that's how you travel between continents

Alternately, EoTN travel is done via the whirlpool. Its a blue swirly(like a flushing toilet) symbol that'll appear near where you enter the crevice and Boreal.

That's an Asura Gate, not a whirlpool.

Thank you all! I just got stuck in that New or Old Ascalon a while back playing Prophecies and have been nervous since to move onto new areas. Thanks again.