Just for discussion, since who really knows, but even if she had planned a suicide trip as you mentioned (snipped below):
Her crash in Haverhill may have been an eye-opener, suddenly she's trying to actually stay alive (if even to find a way to complete a planned mission of self destruction) - and in a strange irony IMO was taken before she could.
I would agree with anyone that the wreck in new Hampshire was unplanned.
I don't think Maura set out to stage a car accident because nothing supports that.
having said that, the question then becomes what happened to Maura once she had an unplanned accident that threw off whatever her initial plans were?
I believe any scenario becomes possible (post accident), however, I go back to what little evidence is believed to be known.
It is believed (by family and investigators) that Maura took a backpack and some bottles of alcohol and nothing else (leaving everything else behind in her car or back at her dorm) from the accident scene.
In what scenario that you can come up with ... does a stranded motorist take a backpack and a few bottles of alcohol with them and nothing else?
If she was going for help, what do you need a backpack and bottles of alcohol for?
If she was meeting someone, you mean to tell me you aren't going to bring your personal belongings and valuables when you enter your friends car, just a backpack and some bottles of alcohol. I am pretty sure a true friend would want you to get your valuables and clothing before you leave your stranded car and would take the additional minute or two to allow you to get that stuff before you leave the area.
If she is hiding evidence. Why not chuck the bottles of alcohol in the nearby woods as you walk away from the car, there are plenty of hiding spots where Maura went missing to conceal a couple of bottles of alcohol. And why do you need your backpack as well.
I can only truly think of one scenario that makes sense when it comes to having on your person just a backpack and some alcohol and you are in the mountains ... and it does not have a happy ending.
The question then becomes, how did Maura go about it.
My own theory is that she caught a ride away from the accident from a stranger. The stranger didn't have to know what Maura was up to, didn't have to know what was in her backpack. And the stranger could've easily taken Maura further down the road, or to Maura's intended destination and that was the last of it.
Because of the location, I would venture to say, that Maura could've been picked up by someone (not local to the area) and therefore, that someone may have never heard anything about Maura murray before in the media.
They just happened to be a good samaratin that night and have never thought back to that night again.