W1: Grab the secret whistles in 1-3 and 1-f as per the category requirement. Then finish the world.

W2: Nothing special here. Try to avoid the music bro, and optimally the hammer is on the upper right.

W3: You want to avoid the starbro, as you do not need him to get the right bridge pattern. You need to cloud 3-6 to 3-7. After grabbing the secret cloud in 3-7, cloud back over 3-6 to 3-8. If you wind up having to fight the starbro, you need to cloud 3-f2 to 3-8 rather than 3-6 to 3-8. Runaway bro is not that big of a deal here, so long as you avoid fighting starbro.

W4: You want to fight the cloud and use your music box before 4-4 to avoid the other two. If you are not comfortable about surviving 4-4 or 4-5, use the music box after 4-4 for extra safety :) You need to enter the secret tanooki room in 4-5 with Fire Mario or Super Mario. Clip the upper right corner from the giant question block to get to the secret Japanese end card. After 4-5 whistle straight to W5.

The cloud in W4 is the new and improved runaway bro. If he runs left and mixes with the other two, you have a terrible run!

W5: Equip your P-wing from beating W1 before entering 5-1 and grab the secret music box. Use your last two whistles to warp to W8.

W8: Optimally you need to grab fire in the navy and use your cloud on 8-f. If you do not have fire after the navy, and you avoid hand 3, the fastest way to have fire for Bowser is to use your star in 8-1 and grab the early fire flower. Alternatively, you can cloud 8-2 and play 8-f to grab fire there.

Good luck!