Oh, I'd not thought about Rory and Amy meeting up with River in past New York. Ha, that could work too... is it still 1969 when River "dies" in the alley? And if so, Amy and Rory could find her, then pick her up and take care of her as a little girl, and then send her off to Leadworth to meet up with them as kids again. Um, assuming Melody ages really slowly? Arg, I'm going to retconn things in my mind until this works...