Super Mario World/Forest of Illusion/Blue Switch Palace
This one is a walk in the park, not to worry, only spiny's here with 2 p switches, silver one makes the Spiny's into silver coins and the other turns the coins into blocks (as you see in most levels) Get all the coins, and you get an extra life! The Big Blue Switch found here creates blue blocks which help get three 1-up Mushrooms in forest secret area, and they are helpful in entering Special World.