mysql query from wordpress page using custom table

I think if you add a couple of periods before and after the php variable in your query, remove the use of mysql_fetch_array, and use get_row(), it should work better. Here’s how I would get a park from your custom table:

<?php
$page_title = wp_title('');
$park = $wpdb->get_row("SELECT * FROM $wpdb->park_data WHERE park_name="".$page_title.""");  
if($park)
{
   print_r($park); // because other than it being an object, I'm not exactly sure what's returned.
}
?>

Also, keep in mind that the mysql query assumes the wp_title() returns the page title formatted exactly the same as the park_name stored in the DB. You may need to format wp_title() to get it to match up with your table data.

It looks like you just want one park returned so I used get_row() instead:
http://codex.wordpress.org/Class_Reference/wpdb#SELECT_a_Row