You most certainly do not need a rogue for the elevator, but you do need one (PC or shroud) for the upper level.
Castle door requires a pick lock skill of 201 or the use of of A Stone Key, which drops off of Captain of the Guard.
Elevator door requres a pick lock skill of less than 100 or the use Key of Torsis, which drops off of Neh`Ashiir.
Upper level areas door requires a pick lock skill of 201 - there is no key for this door.
( Summarized from http://www.eqdiva.com/Forums/ShowPost.aspx?PostID=76864 and http://home.fuse.net/verdandi/compend.shtml )