All I can say is try. We have eaten at 1900 Park Fare at opening and there was always a long line to check-in and wait for the doors to open/get your picture taken. It also depends on the time of year you are planning on going...if you are going at a crazy busy time of year then I would say your chances would be very low if any at all, but if you are going at an off time of the year, then your chances would be a little bit higher. The problem with 1900 Park Fare is that it is a popular character meal (both for breakfast and dinner), but you never know, there may be some last minute cancellations which will allow you to get in. I would keep stalking the dining line (call and go online) many times a day, you could even keep checking while you are there by going to the front desk...if not then I would make sure you have a plan B. Good luck.