Lower Roshamuul hunting grounds are all areas between Inquisition base camp and the bridge. It is accessible immediately after going up the ramp from the camp. This area is small but open and extends west and east from the ramps. To the east are more ramps that go down to the ground floor level which is mountainous and has access to some strange underground caves.
Once the bridge is repaired it leads to Guzzlemaw Valley then to Upper Roshamuul (see each Game World for its current stage).
This area is dangerous so a suggested level is 200.
The ground floor area can be crowded so utilise the caves and note that they do not always exit where you entered.
One underground cave has Lava Holes which attack you. Enter the Instable Vortex at the far left end to escape.