Being a Floridian, allow me to attempt to shine some light on the ground conditions here.
Because we are flatlanders, with very low elevation to water, mostly swamp woody areas, etc...if there were a drought before TS Fay (which I'm not even kidding about how much rain that dropped on us) the area would become saturated...now take in consideration, no where for it to run off, and the ground literally cannot absorb all the water. Alot of it evaporates with the heat and humidity only to return as torrential downpours. The picture of the area where they found her, is unfair to describe as "woods" it is much more dense, with sharp saw grass and palms....and totally snake infested. All kinds of critters live in there. It is very believable that the area remained unsearchable long after Fay. I also don't doubt that the body dislodged and was either dragged by possums/field rats (NYC Subway size) gators, and even some very aggressive and angry hawks, buzzards, you name it. Think of how a machete may be used to get through it. It sounds like the bag had been breached as it's said to have been duct taped but the skull rolled out. I noticed on a live shot how far in the forensics teams went...so they probably agree this bag covered alot of ground.