I am not aware of any maps, I do know there is a pic on the web for the bridge.
Best you can do is go there with some one that knows the place.
(yes, I know my way around the place, but currently I would only go there for healing.)
if you have a more specific question about the place other than a map (i dont know of a map) then ask away. for example, to get to the marcimex and/or mind reavers you need to stick to the main path except for one room where you have no choice but to go through a group of thorifoid.
this is the drawing showing how to get across the bridge, you need to start from the bottom of the image and move towards the top.