I've seen him only once at the autopia quest track and that was they day after Tomorrowland just opened. He was in the room for a couple of minutes before he waddled away. His appearances are completely random and he usually doesn't stay in one place to long. It seems though that he really doesn't appear in VMK that much anymore. My best advice is just to keep your eyes peeled!
OK.. some people have seen Push, some haven't.. im assuming it's just a random thing, I guess it's just timing, no particular day or time to be there.. wait - were getting worked up over a TRASH CAN? YAY!