I haven't seen a spot lately but directly across from casey is an old fast pass area that anyone can use now. It never gets crowded and really easy to sit on the ground and see everything so it should work out great for wheelchairs. It's the same view just on the other side of hte hub as the desert party. It's never let me down that there is room to fit and sit there. I can't really think of a better spot for wheelchairs as they really pack the hub tight these days and where you can find a spot with nobody directly in front of you usually has trees.. while not in the way for fireworks, they are very in the way for the projections.