What I think is most important is the breakdown of a theory - once broken - it leaves remaining less possible explanations. Hopefully the break down will be solid.
I encourage more theories, an examination of them, and hopefully some progress towards the truth will be accomplished through teamwork.
Let me see where I think I still be afloat and where I might have some leaks.
BF, When I read your posts I thought we seemed to be on the same page. I've been thinking about his case for the last couple of days and it strikes me as odd that she took a week off to be alone. A week is a long time for a college student to be alone and that decision in itself is troubling. I could better understand her taking off a weekend, but not a week. To me, it points to either suicidal thoughts or the theory that I've already mentioned several times that she was going away to be with an unknown 'friend". In either case I can see her refusing help---IF she did in fact refuse it.
Perhaps my saying that what you are saying makes sense in my mind could be a waste of posting space - but I'll say so anyway.
The dent in her car is odd (appears to be a flat-bed truck type of dent, maybe a tow truck)
This is something I've failed to consider. Lacking an expertise in accident forensics, I don't know what to make of it. She was in a ditch, who knows how that would impact a car.
I have not seen any reports of, or lack of any pre-existing dents. Does anyone have more information? Very possible I missed such a report.
If she was rammed, I believe that whatever happened to her was completely unrelated to anything prior to her arrival near where the car crashed.
Perhaps there is some one that knows that her car had no dents prior to the trip - and that there is no possibility that the dents could have come from anything other then what you describe. I would favor that information at least before I consider it likely myself.
Wasn't that a rural area where her car was found? I mean pretty isolated? Seems like that is what I remember but I could be thinking of someone else.
If it was though...traffic might have been few and far between.
It has been established that although a rural area, however, at least two of her neighbors took notice of the crash.
Does anyone know for sure that she had been drinking or did she buy the alcohol to drink when she got to where she was going?
New Hampshire police searched her computer and saw she obtained directions to two locations in the New Hampshire/Vermont area.
Even if there was an open container in her car she could have opened that at home and not even drank while she was driving.
I feel her not asking for help when she bought the alcohol alone is a material piece of evidence. That most importantly tells me her trip was made of her own free will.
In my mind, where she drank only provides a possible motive to flee the accident scene.
That would explain why she was so upset at work that day - maybe the guy showed up, maybe he called, maybe she saw him lurking around and it upset her. She decided to go away for a week in the hopes of just getting away from the situation...It is possible she knew she was being stalked by someone but she didn't really know what they looked like so she was scared of getting into the car with anyone she didn't know because she couldn't be sure they were not the stalker.
The telephone calls made to her the night she disappeared have been identified and discussed.
Chances are about equal in my mind that (if there was foul play) - the foul player knew her in Massachusetts and accompanied her. However, the reason I believe she felt amicable with her possible accomplice follows.
The only motivation I could imagine for her not telling her father that an individual had some type of interest in her (either 1. A true relationship or 2. A creepy stalker) was that she had a motivation not to tell - perhaps ambiguity or inner conflict as to who she would choose.
However, I can see that you have pointed our a possibility here.
I don't know what made her so distraught but if she was upset enough it doesn't appear to matter whether or not the car was banged up, she was going. That's part of why I don't think she left the Amherst area with someone else. As Bobbisangel said she probably would have left with someone else in the case.
Although the evidence indicates a suspicious car was around - I agree that it doesn't necessarily mean that the suspicious car is a car involved. It is slim evidence true, slightly possible I suppose.
Under speculation - her accomplice (or accomplice turned adversary) could have driven with her in the car. I don't know if uncontaminated car forensics were performed to tell us with certainty - but it would help weed out possibilities.
However - I speculate it would be possible that a plan was put forth to part ways after the week off, requiring two cars.