Ya right there Juro.
More people need to start to look for moving water along the shores of every dammed up river. We all seem to just look at free flowing rivers but I have found steelhead holding in the Columbia along the reservoir side of dams where rock out cropping and gravel bars stick out into the lake. Seems like no one ever fishes this water but heck it's so easy to swing a waker through the current. It's amazing how many fish can be hooked along the shore even up by Clarkston if you just look for where the original river hits up against the bank. Usually just driving the road one can see water movement along the shores for a hundred feet or so before it turns back into a lake again.
As for the first light thing you are right on, even a half hour earlier than the 1st bit of evidence of light. Of course standing in the Snake or Clearwater in total darkness is dangerous fun and a mistake can cost you your life. But it is amazing how steelhead can see a dark colored fly fished just under the surface in the dark. On good days on the Snake one can hook 3 or 4 steelhead before the first jet boat starts its noisy run at 0730 just 20 feet from you.
Better jump on a plane and come back out again !