I think they'll say that KC was "thinking" of getting involved with drug smuggling, some illegal activity, she and Caylee met up with this guy, he lays out the terms (she'll be very detailed), she changes her mind, he gets angry, somehow Caylee gets killed. He dumps her body in KC's car, they go to a bridge, he dumps the body, then threatens to kill her and her entire family and all her friends if she tells. There - she didn't do it, and was afraid to tell.
Would I believe that garbage? NO but it would create reasonable doubt. She'd still be facing serious charges, but nothing like murder 1.
She could explain all her strange behaviors, like partying like a rock star, and stealing Amy's checks and shopping away in that she was in shock and shut down emotionally. Wouldn't quite explain how she never broke down and cried for the loss of her child, but my imagination has run dry on that one. JMO