The time at which Joanna was placed by the quarry is obviously a very important point. Media has reported that she was snow covered and covered with leaves, but there is speculation that she was not covered at all. We do know that per reports she was frozen solid to the ground. I've been trying to remember when I've encountered something frozed in the snow, and can't get a clear memory. I've considered doing an experiment, as the temps overnight tonight will drop to just below zero and it will snow, but I can't think of anything that would be frozen solid in the morning if I put it in the snow this evening. Any suggestions? I'll do an experiment and photograph the results to see whether something that is already freezing temp, versus something room temp, freezes to the ground. I'm not willing to sacrifice any of my dogs, but what about a grapefruit - one that is outside all day and then put in the snow, and one that comes from a warm environment and then put in the snow.
It seems to me that if Joanna was frozen solid when she was put on frozen ground, she would not freeze to the ground. My guess is that she would be frozen on top of something else that was frozen, and she would easily move on that frozen surface. On the other hand, if she was body temperature when she was placed on the frozen ground, and her body slowly cooled to freezing temperature, then it seems more likely that she would be frozen to the ground. That is, her body temperature would melt or warm the area below her, and then as her body temperature fell below freezing, the warmed area below her would cool with her and then she would be frozen to the ground.
If I'm correct, then this would mean that she was put where she was found shortly after she diied.
Although we don't have a true description of injuries, by all accounts she was strangled and had three partial DNA samples on her body. If that is the extent of injuries and evidence, I doubt that she was kept alive in a third location. If she was kept in a third location, in a duffel bag, but not alive, she would have had to be kept at above freezing temperatures to freeze solidly to the ground ... so not in the back of a car.
Given what we know, and based on having had things both frozen and not frozen in the snow, I would conclude that she was placed near the quarry either shortly after she died, or shortly after leaving a room temperature environment.