Makes No Sense (Spoiler)
All the missing hikers and the State Police or FBI haven't torn that whole area apart? Then the liver cancer guy had a relative taken by them, knows who they are, and zilch was done? Then the father and daughter escape after a handful of her friends got killed and nothing was done? They knew exactly where they were.
The father goes in there with no gun or State Police help knowing they are very dangerous and probably have his daughter or already have killed her? I know it's a movie but so far fetched.