AS the previous poster stated, you cannot just show up, at least not at WBC. You could possibly do it at the hotel building of Wyndham Grand Orlando but it is just a studio room (I believe).
The best thing to do is go to TUG (Timeshare User Group), join, and ask on the boards. You will most likely find Gold or Platinum VIP owners that are more than willing to check availability, book at the massive discount rate, and get you something if there is inventory. The advantage of a PlatVIP owner is they can book inside 60-days for 50% of the points AND get a free room upgrade based on inventory. If you are booking a 2BR Dlx and the only upgrade available is a 4BR Pres, they can book the 4BR Pres at 50% of the points for the 2BR Dlx.