I've had thoughts along a similar line, because people watch the news or hear about cases in the news somehow. If someone hasn't been thinking that this might happen to them and then it does, what goes through their head?
What recent or local cases come to mind? Does she think about Sherin in a culvert, Mariah in water and think to herself that as they were found they obviously weren't good locations, what would be a better location for her to choose? But I also think someone like her would be limited in the amount of thinking they could do about it, because I think she should still be more in a panicked mode? Would she be able to think "I rule out this location because I go there too often and people would associate it with me?"
I almost think we should ignore Sherin's location, it's so close to the home that it makes me wonder if WM subconsciously wanted her body to be found.
Mariah's location feels like it ought to have more insight, and EK went quite a long way for a child that wasn't his own, and he chose a watery grave in a place that was familiar enough to him because he'd gone fishing there in the past. That's why I'm sort of thinking that it might be a place from the past where there's familiarity with the locale but not frequented so much recently.
I presume she was already thinking of reporting and trying to make it seem like a stranger abduction (or maybe a relative abduction related to the abuse allegations), but I don't really think someone in that state can try to get into the mind of a stranger abductor other than through memories of cases in the news? But most child cases I'm aware of in the US in recent years have traced back to close relatives (not all).
Another, unrelated, thought I've had is that when JH got back from wherever he was, he went back to the house and to EG. They would likely have been together for a few days with her telling him that Lucas must have got out and then been abducted. She must have had some balls to do that, to offer him comfort, to pretend guilt but not too much, to ask for comfort in return. She has LE questioning her about everything she did in the last 48 hours, where she's been, who she's been with, whether she's seen any suspicious people or cars around. And at some point LE start questioning her as a potential POI, and then an actual POI, and she's sitting in an interview room for hours with LEOs trying different tacks to try to get information/confession.
All I can imagine is her repeatedly saying she had nothing to do with it and they have to look for the real abductor. Then she's Mirandized and she has a lawyer sitting at her said saying "you don't have to answer this question".
All I can hope is that they have found some evidence in the house or car and can say to her "if you confess now and give us the location, you might get a lighter sentence, but the longer you hold out the worse it will be for you."