I have become familiar with all other levels in the 11 exit run, but the Bowser level is in my way. Do you have any specific route (until now I've always tried going to room 2 and then 5 with the cape). Then in the Bowser fight, I am just way to slow. Are there any videos that show this?

This video is a good guide for the fight itself:

Most players go room 2 (sometimes room 3 if they need to pick up a cape), and either do the damage boost in room 5 or fly through room 7 depending on available powerups. Have a look at the various strats here: https://smwspeedruns.com/Front_Door

Thanks! I'll try this as soon as possible