Hi Steelman, Glad you decided to join the discussion.
To answer your question about the cell phone records. The investigators requested a search warrant/court order for the phone records right away. It took a couple of days for them to get those records.
Any other cars have been accounted for. We don't know how many they have. So there are no cars missing.
The scenario that Mom was given a ride, either willingly or unwillingly, to the father's house and somebody called Greg to have him go there is likely. Hopefully, LE have the phone records to see if this happened. However, if there are landlines at the father's house and Greg's house are phone records available like they are with cell phones?
From the descriptions of her being very independent and preferring to drive herself and both of them being very private people, I don't think she went with whoever it was willingly, unless maybe they told her that Greg was in trouble or something along those lines.
Yes it does sound like Greg left suddenly. If the reports of him being seen leaving his home at 10 pm are true, why did he have a roast cooking at that hour? What was he so busy doing all evening - until 10 pm - that he didn't have time to eat? I wonder if they have been able to track his movements throughout the day.
The robbery attempt could have been unrelated, as you said some criminals take advantage of things they hear to know when a house is vacant. However, why would a burglar attempt to take clothes, towels and pillows? Also the homes are very close to neighbors, so they aren't particularly easy targets for robbery.
And one last comment - this is small town Montana. It is unlikely that there are many security cameras around town.