P1: Fork right after the first bolt on pitch 4 of Cory's Groove and head towards the unmistakable Hoover Dam. With a 70m rope, you can avoid the first set of anchors you see and go straight to the ones at the base of the dam.
P2: Follow a runnelled ramp to the dihedral on the right side of the Hoover Dam. Belay your second up from a tree on the large ledge atop the dam, or at another one just below that (depending on rope length and whether your belayer walked up the ramp). Rappel twice down the middle of the dam face to get to its base (70 m rope mandatory).