Kissimmee /disney

Hello all. First trip to Disney but we’re only going 1 day. The other days are hopefully a day on gulf coast and day in Atlantic side. Then a day of rest. Trip is March 23- 29. Son in marching nband and they are going to Disney. Whole point is watch them march. Anyways I’ve tried three places to stay. Wilderness, great oak and mill creek. No openings. Anyone have a spot they like that’s likely to be open? Any help would shorten my search. Thanks!