I wanted to bump this rather old topic to post my completed TAS for Super Challenge World (any%, not 100%):
http://dehacked.2y.net/microstorage.php/info/578415363/Super%20Challenge%20World%20TAS%20any%25.smv
My route was to get to Twilight Fortress (since I found a way to get a cape out of that level), and continue on to the end as quickly as possible. I think the total exit count is either 42 or 44, I can't remember exactly.
Total time: 1:06:27
Rerecords: 57395
FAQ
Q: Why did you wait until after Eerie Castle to get the yellow switch palace?
A: The secret exit in Eerie Castle is much faster without the yellow blocks. Putting the keyhole underneath a set of yellow blocks was meant to be a decoy/joke, but it turns out to be very convenient for the TAS. I can't skip the Yellow Switch Palace entirely because it's necessary for getting a cape out of Twilight Fortress.
Q: Why do you die at the start of Whomp's Fort 1? Why do you sacrifice your cape at the end of the level?
A: Mario has to be small to complete the level because of 1-space tall passageways everywhere. I brute-force the section with the fish blocking the way (by switching to cape and getting hit) so that I don't have to get the silver P-switch. The time lost by not having a cape in the later levels is offset by the time saved by not getting the P-switch.
Q: What's going on at the end of Mystery Passage 3?
A: It's necessary to set up a glitch to progress to the end of the level: If Mario is holding onto a rope that collides with a wall, the game locks Mario in the "climbing" state even though the rope is gone. The effect is that the game "thinks" that there are now invisible climbing nets everywhere in the level. If you see some weird flight patterns in the area with the plants, it's a result of the glitch.
Q: Why do you wait so long in Mystery Passage 4?
A: I have to wait for the crushing platforms to rise (it's impossible to swim under them, unlike regular walls and platforms). Since I have to wait anyway, I kill some extra enemies to reduce lag.