Rhydon is, in many ways, superior to Golem becuase of better HP and Attack. Eviolite also adds decent bulk to him.
Here's a moveset I would suggest:
EVs: 252 Atk, 252 Def, 4 HP
Ability: Rock Head (for lack of a better ability, Solid Rock is best but that's for Rhyperior)
STealth Rock and Roar is a great combo, Toxic for stall. Earthquake and Rock Slide are to slowly whittle away the opponents HP.