It's really hard to unpick it. From one angle, the whole thing looks quite elaborate staging to me - arranging flowers to be sent with no note to her stepmum (NOT her dad apparently) 3 days after she'd gone away, notes placed or found under a bush (it was raining and stormy the night she disappeared so how did the notes survive?), vermouth (who would choose that to wash pills down with) and paracetamol (which would have caused her agonising stomach pain, severe headache, confusion if she had really taken them).
The credible sightings of her after she went away suggest that this was some sort of staging rather than real, but that is quite a devastating thing to do? And she never came back? It would suggest she was really, really angry with her parents. One of her friends did say that RW was a bit of a drama queen, whatever that means. And I can sort of get her doing that to her parents but what about her sister?
When you look at it that way, it looks quite extreme, but she was a teenager, had had a massive shock. She had run away before so clearly was very unhappy, and for her parents to say they don't recognise this version of events is either them covering up or being pretty clueless or just plain in denial.