I'm stuck on Crystal Version.?

I need to find out where to get a rocket costume to beat the tower in goldenrod because thats the only thing I can think of to get the candybar guy in the next town to let me p through, I also didnt catch sudowood and I think I need to in order to crush the boulders in the game, but there was only one shot? I've searched every building in goldenrod and went underground, nobody is dressing up pokemon or will give me a costume.