Allusion is not Illusion

This is an all right light read if one can get past the fact that the "suspense" plot is predicated on almost all the characters being utter morons. The heroine, Beth, was okay, but everyone else seemed so dumb and one-dimensional I just couldn't believe they were real. The story opens with Beth and her brother Ben camping on a small island with his daughter Amber and her best friend Kim. Beth and the two girls are walking and stumble over a skull. Immediately a muscular stranger appears and starts chatting them up, pretty obviously digging for information about them: where do they live, how long are they camping, are they alone? When Beth tries to avoid giving Keith this information, the girls act like she's being weird. Okay, they are supposed to be fourteen and boy-crazy, and maybe yeah, they are from a very safe, nice suburb (of Miami, note), but this is exactly the stuff my parents drilled into to me never to tell strangers. "Are you alone?" is the only question I can recall being explicitly told I should lie about! When the three get back to camp Beth tells her brother about finding the skull. Their conversation goes pretty much like this:

Beth: "I found a skull buried in the sand."
Ben: "You imagined it."
Beth: "No, really."
Ben: "It was a conch shell."
Beth: "It still had flesh on it!"
Ben: "Sigh. Women are so irrational."

The Keith comes back and invites them to eat with him and his two buddies. Also joining them are rich-bitch flirt Amanda who frequents the yacht club where Beth works, her father and two cousins, and another couple unknown to anyone else. Keith tries to find out more from Beth and her family about where they live and work, and also insists she did not see a skull. That night Beth wakes up and hears someone skulking aorund her tent and screams, and everyone acts likes she's crazy, including Ben even though he later admits that he also heard something. The next day everyone says they're going boating except Beth, who goes to search for the skull. Keith claimed to be boating but in fact hides in the bushes and grabs her from behind. She doesn't bother to tell anyone about the incident. Which, I guess all evidence suggests that her loved ones will just dismiss her story once again, so I understand why she (like many women who are assaulted in real life, sadly) has given up trying to get help.

After the weekend the family returns home. Someone breaks into Beth's office, searches her computer, and leaves a threatening message. She calls the police.

Cop: "It was a prank."
Beth: "But someone broke into my office! And left a skull on my desk!"
Cop: "Just a prank."
Beth: "I want you to take a report!"
Cop: "Don't wanna."
Beth: "I insist."
Cop: "Sigh. All riiiight. Geez, women are so irrational!"

Note: Ben is present, and someone has broken into his locker earlier that day, but he does not mention this fact.

When Beth gets home that night someone is lurking in the bushes. She runs inside and locks the door. The person hurls a dead animal at her door. Almost immediately her brother comes to the door. She is upset and he yells at her.

I'll stop because I don't want to give any spoilers for the rest of the plot, such as it is. Pretty much goes on in this vein for 300+ pages, with a few really fake sex-scenes.