Super Mario World/Vanilla Heights/Vanilla Secret 2
This Level will be much easier together with Yoshi. It's pretty simple and there are no hard riddles in it, but you will have to either dodge or jump on the flying Koopas all the way through it.
However, this level is perfect to boost up your lives. Probably the easiest way to do this is this one:
1. Go to the Star Road and get the blue Yoshi from Star World 2.
2. Go back to Vanilla Secret 2 and enter the level.
3. Eat the one Koopa at the very beginning of the level and immediately start to fly above the level (Make sure to look out for the fishing Lakitu, fly above him, but fly low enough to see him at the bottom of the screen.
4. As soon, as the fishing Lakitu stops following you, you can descend with Yoshi and walk to the right, until you reach the pit with the 10 Spinies in it.
5. Above the Spinies are 4 yellow boxes. Hit the second to get a P-Switch.
6. Take the P-Switch and move back to the left of the level. You will reach two purple tubes after some time (Make sure, Yoshi doesn't swallow the P-Switch.
7. Jump on the P-Switch, once you're at the purple tubes and run to the left, collecting all silver coins.
Depending on how fast you are and how many coins you collect, you wil receive somewhat between 30- and 55-Ups.