Depends on what your interested in.
For mainly hard parts (ie blowers, speed parts etc.) the main hall is the place. For soft parts (radios,nav systems etc) the north hall is the place. Tires and wheels are in the south hall. The service industry (motorcraft, bosh, oil etc) is at the Sands convention center. There are shuttle busses running all day between LV convention center and the Sands convention center.
It will take you all week to see everything, so wear comfortable shoes :biggrin