I was one of the very few ppl who did not win a golden ticket, the email I received friday the 15th gave a link to print the 2 free tickets to Bizarro Preview Day that I won and gave me promo codes to do so.. As for the directions to get to this event (which I believe would be the same as those who won a golden ticket), they are as follows...
Go to Six Flags Great Adventure on May 21st and ride Bizarro -- for free!
Enter through the main Six Flags entrance and stay to the left when approaching the Main Gate toll plaza. Proceed to park in the lot directly next to Kingda Ka and the Great American Scream Machine. There will be a sign in table located at the gate in the parking lot next to Kingda Ka.
Plan to arrive at 9:15 a.m. Also, if at any time you are unsure about where to go, there will be signage and staff directing you in the park.