In the right, upper wing, all the way to the end area where the Arcanus spawns, you will find the book in the shard chest room. It is on the floor and when clicked, you will receive: Sailing with Three Sheets to the Wind. You can pick the book up at level 75 and receive the quest, however, you can not enter Nu'roga until level 80.
Make sure you still have the book that starts the quest on you or he won't talk to you.
Rotheck sends you to gather the following items to make a necklace for him:
12 blue sapphires from Nu'roga. The entrance to Nu'Roga is just within the Mines of Nurga. Enter the tunnel and, a few feet in, turn right and follow the tunnel. The sapphires drop from small wooden chests, so be sure to check these and not ignore them.
Queen Lenya Thex is located in a 'hidden' room with a 'locked' door that only opens after you've killed most, if not all, of the named in the Manor. The named in the Main Ballroom is hard - we never did kill him after several attempts. We cleared the rest of the zone, finishing at the top (where the void shard chest is located). In that room we found a 'hidden' passage behind a bookcase (44.8,26.3,-376) that slides away when a candelabra sitting on a table near the bookcase was toggled. This passage led back to the previously 'locked' hidden door that led to another passage to a room with Queen Lenya and two named in it.