A couple of people have had questions about the speculative timeline I posted a while back. Again, haven't time to go back and find them to respond properly, sorry.
How certain am I about my surmise that Chad flew to Mesa and drove back in the Jeep? It's the best surmise I have in the absence of hard evidence. The flight schedules do not seem to make a turnaround possible in time to be with Lori and MG at the track. And if he did fly down and drive back, the Jeep was the most likely thing to be driving back in.
What about my surmise (not flagged as such, sorry) that DW drove to Rexburg? Again, flight schedules back to AZ and the fact that the babysitter did not mention him.
Why didn't the babysitter see MG's luggage? (extra bonus explanation): It think the luggage was in Alex's truck while Lori was trying to hustle the babysitter out of there.