My bolding. This is the stumping question. There is only a couple answers to that, if one wants to assume that DB is responsible. Either she acted alone, which I've already said I think is near impossible OR she had help. Since she could not call out to arrange for help, the only other thing I can think is that someone (like Phil) was already in the house or had an unplanned stop by.
Another unknown for me is I don't know how thorough searching by LE is. I am assuming that it is very thorough, and if BL was disposed of in the 1/3 mile radius, she would have been found by now. Maybe I am giving LE searching too much credit.
I am also wondering about the dogs that went on the searches. Were they tracking dogs for picking up BL live scent or were they cadaver dogs? I think that if she is in KC and not in the river, her body will eventually be found.