From what I interpreted of Nick's (the AWP diver who found KR's car) statements in the Duty Don video with the two former NYPD Detective hosts, KR's torso was up against the floor of the hatch / cargo area, which would have been the highest point in the car while upside down. Her legs appeared to be dangling down and so that is all he saw through a side back window. He first saw shoes on the other side of the hatch, IIRC. But we don't know if saw feet or if the legs were clothed.
And as an OP today pointed out, the former NYPD Medical Examiner Chief of Staff (not a physician mind you) said in that same interview that from Nick's description it sounded consistent with bloating from decomposition; that after two weeks the torso would drift up to the "top" - which in this case is the bottom of the car. That is if she was there for two weeks...
All that said, I still wonder how KR got in the hatch given the limited time she likely had and what it might take to get a body, live or dead, from the front seats. Perhaps she was originally in the back seat? Just pure speculation on my part.
So many mysteries when you consider we have NO NEW facts from LE or MSM post KR's remains being confirmed (8/23).