Does anyone know of good textbooks to use for the test portion of this event?
I would probably read Wikipedia and familiarize yourself with the different simple and compound machines. Wikipedia also has all the equations you need, some derivations, and explains concepts pretty well in my opinion. I think the equations and concepts are not that hard it's just finding practice problems. To study energy you could use any good physics textbook like Giancoli, Resnick and Halliday, or University Physics (Young and Freeman). Make sure you understand concepts of Mechanical Advantage, Ideal Mechanical Advantage, Real Mechanical Advantage, etc. really well and know all the equations for each of the simple machines.