Okay, now I'm on a speculating turn, so here we go!
From the first scene with River and Rory when she's returning to her prison cell, I got the impression that somewhere down the line, the Doctor gives young!River his journal (because she knows about Demon's Run, but she isn't going to be there, hence that journal is not about adventures as told from her POV, but from his). The reason River knows about Demon's Run is because the Doctor chronicled it. Even her recitation of what happens at Demon's Run sounds like she was telling a story written for a child. And I suppose this seems obvious, but I get the sense it's young!River in the spacesuit who kills the Doctor. That's why he's so accepting when she does it, because he's risen so high, when rising high means the name Doctor means Might Warrior instead of Healer, and so falling so low is about restoring his humility.
So young!River killed the Doctor. I wonder, was it a pistols at dawn sort of thing? Where young!River had to kill the Doctor to be set free from her captors, from her first prison.
In this episode, River tells Amy that the Doctor will save her. And now I'm imagining him meeting with young!River in the spacesuit and making a plan to help free her where the price is her fulfilling what her captors intended: using her as a weapon to kill the Doctor. I'm remembering that tone in his voice when he's facing his death in The Impossible Astronaut, it's almost like he's reassuring his would-be murderer that it's going to be okay to kill him, like he's coaxing the person in the suit to kill him. He's leading a young River to kill him as he'd planned all along and he invites River and River's parents to witness it, and River's "I hate you"s to the Doctor now feel like they're about how far he'll go to help others, but also how his schemes come at a price. She loves him so much for helping rescue her, she hates him for how he did it. The method of her freedom: forced to live with the knowledge that she killed the man she loved. A Good Man.
And isn't that a similar sort of terrible? In the premiere, the Doctor turns the human race into killers any time they see the Silence in order to free humanity from servitude --> coaxing a young child to kill "a good man" in order to free the child from the servitude of her captors.
I have a big jumble of thoughts, but mostly it feels necessary to watch every episode with River Song in it again because it's all been turned on its side and everything's gained a new layer of meaning.