Well, I thought they had expired, but I found our old Costco tickets (3 day park to park) which expire 12/31/14. We only used 2 days, and we are going to Disney for Christmas week. I would like to take one day and go over to Universal. Which day would you recommend of these three? 12/20 (less preferred for us), 12/21, or 12/22? I know it will be crowded, and we won't have express pass or early entry. We can make park opening on the 21st or 22nd , maybe on the 20th, but not sure about that day. We don't need to ride every ride, but the two Harry Potter worlds are a priority. If we don't have early entry, should we try for Gringotts late in the day? Thanks for any and all advice.