[StacyP2006]

I am trying to remember the name of a book I read once, probably around the early 2000s. Can't remember the title or author. I am 99% sure it was a Young Adult book.
Here's what I remember about it:
The main character was a girl. She was being followed by boy I think into the woods/forest. I think she/they eventually came across a cabin or house.
There was a an evil guy that had to be defeated.
The main characters somehow went to a fantasy place while sleeping and in their dreams.
The boy character's father also had this ability but the boy didn't know this until later on in the story. And I believe that he eventually helps them somehow.
I also remember there being some sort of trial towards the end of the book and them travelling through a cave to get somewhere, possibly where the trial was held?

Sorry, I don't remember any names.
Thanks for any help!