One scenario that gets much less consideration is suicide. Most of us consider foul play at the scrap yard, foul play from the scrap yard between being there and 1:45ish when his phone last pinged, to a lesser extent foul play at the garage at 2:45, or he took off, either alone or with someone. The suicide angle is starting to grow on me. I have two examples of suicides that have occurred in my life. The first was a co-worker. He had a TON of money, beautiful wife, beautiful home and two children. He also had a very bad alcohol problem. He drank mornings, hid bottles in places he knew he could access easily. It was very bad. He always said if he ever felt that he'd never be able to beat his addiction that he'd kill himself. One day he jumped in front of a train and did just that. Another example was a buddy of mine who was having marital problems. Friends of his, including me, did not know the extent of the problems. Turns out, after the fact we found out his wife was in another relationship and was planning on leaving. My buddy asphyxiated himself in the garage so that she'd find him. This was SO OUT OF THE BLUE for any outsider. Shocking.
So, we never exactly know what demons people are fighting. Could RM have had a problem that he couldn't deal with? Could he, just like my co-worker, have told IM of his problem and mentioned if he felt he couldn't beat it he'd kill himself? IM's comment "I FEEL the Edgewood Preserve is the place to look" resonates with me. Did he ever tell her he'd go there to harm himself? The preserve is very nearby the train station. Put the bike in the car, park at the station, ride the bike to the preserve. Move seat up to get it out. Leave the ID at home. Perhaps, in his head he was trying to spare the kids by being unidentifiable. If he went deep and far enough into the preserve, it could be a very long time to be found, if ever. I know there wasn't a scent at the station. Maybe if he got right on the bike it would be hard to get.
Anyway, with the lack of any new information, this is the latest scenario rolling around my head.