Thought this might be a fun thought exercise:
What would have the Cooper hijacking looked like had Cooper’s plan worked exactly as he had anticipated?
The money and parachutes would have arrived at precisely 5:00. Fueling would have proceeded without delay.
The plane would have taken off at approximately 5:30. Airstairs down on takeoff? Or lowered in flight? If airstairs down at takeoff, then Cooper likely would have jumped 15 minutes after takeoff at 5:45. If the airstairs were to be lowered in flight, he expected it to be easy to do. His inability to lower airstairs properly delayed him about 10 minutes. So, if the airstairs were to be lowered after takeoff, then he would have jumped closer to 6:00pm
Sunset on that date was at 4:33pm. Even at 6:00 pm there would be enough light to see, but once he hit the ground, it would darken. That was likely his plan. To be off the plane while still light enough to see, but with night quickly approaching so he could disappear in the darkness.
If he jumped at 5:45, he would have jumped in the vicinity of Spanaway on the outskirts of Seattle an and the dropzone would have been near South Hill also in the Seattle suburbs.
If he jumped closer to 6:00 pm, he would have jumped about 5 or 6 miles north of Etna, WA and the dropzone would be about 5 miles north or Ariel. That area is pretty rugged and remote.
This obviously uses very broad approximations and a lot of speculation, but I think it’s a thought-provoking exercise. Therefore, you can’t draw any decent conclusions from it, but it would seem that it would have been better for Cooper to have the stairs down on takeoff as it would have resulted in a landing closer to civilization.
Fact check me, my times might be wrong.