Super Mario World/Star Road/Star World 1
Key
editBy spin jumping along the right edge of the level you will be able to reach the key easily.
Baby Red Yoshi
editA Baby Red Yoshi is found in the bottom portion of the level, but it's hard to get, and will need a bit too much food. If a Red Yoshi is desired, it may be easier to instead find it on really think you should use Star World 4.