With your rhinoroller in Ratcicle kingdom, go up to the gate where the old coot playing the guitar is and where the big rope things that say N on them, use your rhinoroller and roll on with them until two thumbs up appear. do this with both ropes. this will open the gate. go inside the gate and roll all up until you reach the Evil Public School. (Hint, you need the middle cup when your going up the roll thing and you need an IQ mutant,(the levitating one.))
Spin Crash on the digging spot, dig under the gate into the middle where the engine is, crash the engine with your RhinoRoller, dig back out, spin Crash on the orange swirl which will open the school doors for a couple seconds and while its still open run to the gate and climb up it. run into the school before the doors close.