I just watched the SM interview again. IMOO, she sounds so believable up until the hike questions start and she gets her daughter in it. That's when she starts talking a little less smoothly and such and nervous. I really do believe her, strangely, that she didn't hurt him and loved him and those nice things she said about him. But then the daughter/when was he last seen at home/hike/Burger King discussion is when things start to sound really suspicious and weird. I think she knows more than she is saying, but it just baffles me as to WHAT happened.
Weirdest is the "when you get here" - I suspect there was a runaway situation and yet she is culpable somehow too???