I get around the black corridor issue by using autorun. Zoom out and, autorun into the corridor. When you hit the wall in front of you that is the beginning of the first curve to the left, you'll know you've hit the wall by how the camera shifts. Once you hit that, turn very slightly to your left so that your character runs along the wall. Running along the wall is how you know you are still heading in the right direction. Eventually, you will cross the load point. Keep autorunning after you load the next map until you hit another wall then turn right. The is the curve right. You should be able to see the exit onto the next map then.
That method should work for any corridor and on either side of the corridor.