Warning: There are spoilers for Looking For Alaska ahead.
Yes, there are many ways in which Alaska Young is a manic pixie dream girl. Even Looking for Alaska author John Green told me once that he wrote Paper Towns to correct some of the errors he believes he made in shaping the main female character of his first novel. But if you look closely at Alaska's actions, and what happens to her at the end of the story, you can see that she's not a one-dimensional perfect wild child. She's just been cast that way by the boys in her life.
Because the novel and the series are told from Miles "Pudge" Halter's very limited perspective — he's an adolescent boy who wants her to be his manic pixie dream girl — we get Alaska's story out of order. Here it is chronologically:
How Alaska Got Her Name
Because her hippie mother wanted to name her Harmony Springs and her conservative father wanted to name her Mary Frances, they decided to call her Mary until she was 7 years old. Then she got to pick her own name, which she did by looking at a globe. Alaska was her second choice after Chad, which her dad rejected as a boy's name.
What Happened To Alaska's Mother
The following year, when she was 8 years old, Alaska had her "best day ever," when she went to the zoo with her mother. The day after that was her worst day ever, when she saw her mother scream out in pain and collapse on the floor. Paralysed by panic, she sat by her mother and cried instead of calling 911. By the time her father got home, he mother was dead. Calling an ambulance probably wouldn't have prevented her mother's death from a brain aneurysm, but to this day, she feels like it was her fault. She doesn't tell any of her friends about this pain she's carried around with her until she suggests the drinking game of Best Day/Worst Day at the barn.
Alaska & Her Dad
Alaska doesn't have a great relationship with her father, as evidenced by the fact that she avoids going home to visit him and will do anything to avoid being expelled from school — even snitching on her roommate Marya. Her one source of comfort outside of her school friends is Jake, a musician and student at Vanderbilt University. He seems like a very understanding boyfriend, as far as we know.
What Happened Before Alaska Died
On the day of her death, two days after that game of Best Day/Worst Day, Alaska and the Colonel got drunk again and played Truth or Dare with Miles. On a dare, Miles made out with Alaska, which was basically his life's dream. After everyone fell asleep, at around 3 in the morning the phone rang and she answered it. It was Jake calling at the exact moment of their anniversary. In the middle of that phone conversation, while looking at the doodled graffiti by the phone she realised that she'd entirely forgotten to put flowers on her mother's grave that day, the anniversary of her death. She got off the phone abruptly without telling Jake why.
How Alaska Died
Alaska woke up the Colonel and Miles and asked them to distract the dean of students so she could drive away from campus. On her way out, she also ran into Takumi. She didn't tell anyone where she was going, only that she "messed up," and none of her friends tried to stop her from driving so drunk. On the highway, a truck had jackknifed and a police cruiser responding to the accident was blocking the road. Alaska drove straight into the cruiser without slowing or swerving. Upon impact, the steering wheel crushed her chest, killing her instantly.
Was Alaska's Death An Accident?
Because her blood alcohol level was .24, the whole thing could have been an accident. The friends piece together the fact that she was taking the white daisies Jake had given her to put on her mother's grave, symbolic of the white flowers her mother used to put in her hair. At the same time, she also marked up her copy of The General and His Labyrinth with a different clue. To Simon Bolivar's question "How will I ever get out of this labyrinth?" she wrote, "straight and fast." That makes it sound as if she planned to plow straight and fast to her death.
Alaska's friends want more answers about why she died, but even if they knew that she died by suicide or by accident, they wouldn't have a complete answer. The truth is that either way, it was a horrible tragedy. It was not something that just happened to Miles, as he initially sees it. It's something that happened to a girl who had a dark internal life that she often hid from those who loved her.