I think her "plans" were interrupted and foiled when mom found her and called 911. Her half-baked stories and excuses were only meant to be heard by her close family - not LE. She knows that her own family does not have the investigative tools that LE has. She knows that her family cannot easily determine that ZFG never lived at Sawgrass, or even exists at all for that matter.
KC was going to do more things to cover-up but that was cut short when mom found her and called 911. That last-moment plea for "one more day" was not to flee to California or anywhere else. It was to be a day to explain to her family that involving LE in the matter was likely to get Caylee and even them killed. Mom, if we want to see Caylee alive ever again, we cannot put LE on the hunt. Mom, calling 911 will cause Caylee's death. Please don't do it for the sake of our beloved girl. Let's run this recovery operation ourselves and keep the cops out of it. ZFG demands this, and unfortunately we have to comply with it. But mom, here's another important thing... you, dad and Lee can't go out snooping around either. If ZFG catches on to that she might freak out and hurt Caylee. I'm the only one who can actually confront and negotiate with ZFG. If anybody else gets involved, we will lose our sweet girl.