You know, there was a lava stage that was also connected to mystic ruins on SA. Maybe you could base the lave phase after that?
Also, a texture of Radical Highway from SA2 would be really cool on Green Hill Zone. I loved that stage.
Its a cool thought, and I can make it. But GHZ and Radical Highway don't have much in common. And, you can't change the color of the sky in Green Hill zone.
I do want to make Radical highway, but there is no stage that really goes with it, and I don't like using custom stage parts.