VIP Admission will allow for you to use the Fast Pass at 2 of the haunts: The Passage & Haunted Hayride. There will be a short regrouping upon exiting The Passage and entering Hell-Billy. Your overall wait in lines will be significantly less. You also have the luxury of arriving anytime during hours of operation, on your selected night, and going directly to the VIP entrance. (arrive at least 30 minutes before closing to ensure entry).
If you are looking to upgrade your already purchased ticket, you can get a Fast Pass at the ticket booth (subject to availability and price increase on busy nights).