I agree that even if Casey thinks she "knows who has Caylee" (ZHG?) she just doesn't know where <shiver>.h Te day she went to pick up Caylee (June 9th at first, then changed to June 16th-ish later) she should have been at least concerned. But the fact the apartment (#210) was suddenly emptied, cleaned and ready for a new resident to arrive since you last left about 6 hours ago - well then the next step should be Worry. Night falls and the clock strikes twelve and the babysitter still won't tell you where you can pick up your child (if she's talking to you at all) - well now we've arrived at the third step: Panic! The first call to 911 should have been within 5 minutes of Casey arriving to pick-up Caylee at "ZG's apartment", but no, her first 911 call came "31 days" later on July 15th through her mother Cindy's sense of panic.
Even if Casey is calm because, as you suggest, she knows who has Caylee then how can we explain how Casey knew someone well enough to leave her daughter with that person for an undefined amount of time with no compensation yet none of her family or friends who were a part of Caylee's daily life (and financial support) had a clue to who this person is? Even if Casey trusts this fictional person, and was able to party at Fusions on June 20th, just 4 days after anyone last saw Caylee, if neither Casey or the GP's are financially supporting Caylee (food, medicine, diapers?, clothes) who is willing to do that? And even if one could say Casey sold Caylee to a loving couple - where's the money? How come she was reduced to stealing gas and borrowing shovels and friends cars if she had just sold her child?
And never forget the overwhelming oder of human decomposition (according to both Cindy the RN, and a homicide detective with LE) in Casey's car; combined with suspicious fluid stains, hairs and soil samples that LE seem to be keeping close to their chest. How many of us have had our automobiles wreak of something dead + had a relative or friend go missing? Not I, and I hope no one on the jury has either.