Neotev, if you've ever played the actual N64 game and have gotten all 120 stars in it, then you have just eliminated 80% of your problem (yes, that is the actual percentage). Now all you need is the other 30 stars, I assume. The switch star for Rainbow Ride, I think, requires you to hit a star switch just outside of the big house, and then to turn into Balloon Mario and float through a hole in the ceiling of the house. Do NOT bump into anything; if you do, I guarantee that you'll have to try again. This switch star requires timing.