Quoted By:
>World 1: Harvest items(pray for leafs), grab both whistles, get P-Wing for stomping boss, if you can get 44 or more coins in 1-4 you can get a 2nd P-Wing
>World 2: Harvest items(pray for leafs), get hammer and use in upper right corner for whistle and frog suit, get cloud for beating boss
>World 3: Beat first two levels to get the frog suit from the first mushroom house, warp to World 5
>World 5: Collect tanooki suit and p-wing on the first half, hope for leafs or the other tanooki suit in the 2nd half, beat 5-5 with 28 or more coins for another P-Wing, beat boss for another P-Wing
Master this pathway, and you can be at World 6 with a sizable inventory and some options on how to proceed. Even with terrible luck on item draws, you'll still have 5 P-Wings, two Frog Suits, at least one Tanooki Suit, six mushrooms/fire flowers/leafs, a cloud, and a few invincibility stars. You can take on World 6 if you wish. Or you can warp ahead to World 7. Or you can use both whistles to jump to World 8 if you feel you have enough. Or you can use another whistle to go back to World 5 and collect more Tanooki suits and P-Wings at any time prior to entering World 7.
All you really need to do is master Worlds 1, 2, and 5, and you are set for end-game.