Not surprised there's been no attempts at this. This is a tough game to git gud at.

Bombshell Kingdom would probably be the first stop since it has a Golden Eggplant, which would be very useful throughout the whole run...if you manage to keep it. Resetting loses a bit of time but not a terrible amount; that can be used to keep the Golden Eggplant should you lose it.
Other than the crown in the shop to unlock World 0, there's no use stopping there except for granny strats. Depending how things work out you can use the spare coins to quickly buy a Blue/Purple/Golden Eggplant to recover.
With good routing you can calculate how much time/health you'll have at the end of the levels that'll add to your coin total, so you'd only collect what you absolutely have to. The gold diamonds in each level seem to be absolutely necessary to get the golden crowns.

I know this is an old thread, I missed it. Gotta remember that 100% includes World 0 completion as well. Back when it was only Vlacksr and I, that's what we agreed on but neither of us really wanted to run the category seeing how long and grindy it'd be.

Though don't let that stop you, I'd love to see some routing done to this myself.

My first goal for routing this will be to find out how to get the Golden Diamonds, and probably figure out the number requirement for each level.

I may do Any% (No Left+Right) for the upcoming 12 Hour Challenge and will check those out afterwards.