If you have not read my Doctor Who Theory, please read it HERE.
I have been re-watching the whole series in order from when it restarted. I had been looking for clues in Season 4 and 5 to support my theory for obvious reasons, but I found more back up in Season 2 of all places.
In episode 13 "Army of Ghosts," Jackie Tyler (Rose's mum) talks to Rose while in the TARDIS.
Jackie: You even look like him.
Rose: How do you mean? *pause* Suppose I do, yea.
Jackie: You've changed so much.
Rose: For the better.
They go back and forth and then...
Jackie: What happens when I'm gone?
Rose: Don't talk like that.
Jackie: No, but really. When I'm dead and buried you won't have any reason to come back home. What happens then?
Rose: I don't know.
Jackie: You think you'll ever settle down?
Rose: The Doctor never does, so I can't. I'll just keep on traveling.
Jackie: And you'll keep on changing. In 40 years time, in 50, there will be this woman. This strange woman walking through the market place on some planet a million miles from Earth. She's not Rose Tyler. Not anymore. She's not even human.
BAM! Right there. Jackie is describing Amy/River. Amy Pond continues traveling with the Doctor. Her parents are gone. She has no reason to go back to Earth especially with Rory traveling with them. She changes as only a human can seeing what the Doctor sees and doing what the Doctor does. She'll seem more like a Time Lord than a human because all of her adult life was spent with a Time Lord. River is all over the place and clearly hasn't settled down. By the thickness of her diary, we know that River spends a lot of time with him - maybe 40 years. Amy Pond would be unrecognizable as herself, but maybe only recognized as River Song.
Again, I could be totally wrong and they could be going in a completely different direction, but there sure seems to be a lot of evidence pointing in this direction.
I'm hoping to take a class on Science Fiction as one of my electives this summer. I'm really hoping an assignment or major paper will give me a reason to write about Doctor Who. This is the completely arbitrary reason I have given myself to re-watch the entire series again.