Note: this logic does not work (under two possibilities) if she were approached at gunpoint by a dirtbag and told to stay quiet (credit to /u/LilSuzie) - or if law enforcement were involved with her disappearance.
On a cold winter night with no where to go that was warm, Maura Murray had no reason to leave the car unless she was DUI.
Unless Maura Murray was suicidal...and she didn't care what happened to her. I don't think she was suicidal. I think she wanted to avoid a DUI.
Her act of fleeing the scene to avoid a DUI arrest is what put her in danger. Danger to accept a ride from a stranger. Danger to be forcefully picked up by a dirtbag. Hit and run. Dangers from the environment. Danger walking down a pitch black dirt road. Danger knocking on the wrong door. Danger trespassing in a community of gun owners. It is obvious she chose to accept these risks for a reason.
She had every reason to stay in her car and wait for authorities
The police wouldn't leave Maura Murray out in the cold on a dark winter night. If she was sober, the police would have offered her a ride to shelter and a place where she could sleep and eat.
And the fact that she would receive shelter, a place to sleep and food to eat, if she was DUI and arrested, makes it clear that she gave up the chance of receiving shelter to avoid the DUI.
You ask what about if a local dirt bag grabbed her right there?
She would have screamed for help. Nobody heard anything.
The possibility that she was abducted up the road is inconsequential to the point of this post, which is to outline why it is very likely the car was driven DUI. And we shouldn't forget that she bought 4 large containers of Alcohol at Amherst.
You ask what about a tangent driver?
A tangent driver makes little sense. She would be unable to communicate with the tangent driver to allow it to respond in time. She had no cell phone reception. It was an accident. That means it was unplanned and therefore, an event a tangent driver could not predict. She was about 80 miles away from Burlingon, VT and about 50 miles from Bartlett, NH. If a tangent driver was going anywhere, it would be going to Burlingon, VT or Bartlett, NH. So, even if there was a tangent driver, the driver would not be close, let alone in a position to guess where she was - such as to allow the hasty departure we know she took.
She had no reason for her to drive an additional foot with her car running on 3 cylinders, if her tangent driver was going to drive the same way. She refused to drive that car to her mandatory nursing clinicals. It makes no sense for her to continue driving parallel with anyone that could pick her up and had room in the car. So, the tangent driver idea does not make sense, as discussed here: https://www.reddit.com/r/MauraMurrayEvidence/comments/4xxqyl/the_first_law_of_tangential_motion_opinion/
Someone in that car was drinking. The best evidence we have is that it was Maura. Butch Atwood said, far away from any intimidation - in Florida, to Mary Beth Conway, that Maura didn't appear intoxicated. Either Maura was DUI and that is why she fled the scene, or whoever was driving that car DUI fled, and Maura felt obliged to go with the person who drove. We have every reason to suspect someone else drove the Saturn - and I have outlined that idea here: https://www.reddit.com/r/MauraMurrayEvidence/comments/51bz99/someone_else_was_driving_the_saturn_fled_to_avoid/