There is a dining reservation window in the park by the tip board. Check in with them when you get to the park. If you are flexible about when you eat, I think chances are good. That's what I do for Sci Fi and 50's Primetime. It's not a guarantee obviously, but there may be a slot or two open. Two years ago, my parents came down to visit over the holidays when I still lived in Florida. We decided to go to DHS for New Years Eve. I tried for over a week to get an ADR to Sci Fi because I knew my dad would love it. I couldn't get anything. Flash forward to New Year's Eve morning. We stop by the window on our way to TOT and we get an ADR for the 2 of us for 11:45 for lunch!!! If you can't commit to which day in the park, I suggest the dining window. I love it!