Well, if you make it to the point where you chase down Birdo and Valentina after hearing their plan, you can graba star and make it all the way to the end, when you fall down you do not have to go directly to the fight, you can leave Nimbus land and buy some Pick me ups at another town. And this is just me but, I usualy have the "See ya" item to get away from those annoying castle guards.