I think you're all looking at this too complicatedly!
Observe:
On the first page, set an array of all of the pages you want the user to view into a session variable:
session_start();
$_SESSION['pages'] = Array('page1.htm','page2.htm'); // Etc.
On the next page, you do this:
session_start();
shuffle($_SESSION['pages']);
if(!isset($_SESSION['pages'][0])){
// The user has no more pages! Do something!
}
$page = $_SESSION['pages'][0];
unset($_SESSION['pages'][0]);
include($page); // OR echo file_get_contents($page); , depending whether it's PHP or html.
Simple!