I'm still on the fence about whether or not she was killed in the home.
Surely, that would have been one more slap in the face to "Ci-Ci", so it's certainly within reason given Casey's mindset toward her mother. But she could just as easily have killed her elsewhere and brought her home to dress her for burial, so to speak. I think she intended to bury Caylee in the A's backyard all along, and only decided on the woods when she realized how difficult it would be to dig a hole large and deep enough to hide Caylee's remains.
Somehow, coming home to wrap Caylee in her favorite blanket, the heart sticker, etc., helped to assure Casey that she was giving her daughter a loving and proper goodbye. As if that somehow made it okay.
The Tot Mom is a vile, evil creature who fully intended to rid herself of "the snot nose" - this was no accident, IMO.