Complex sentence: Cutler did everything possible to drive his parents apart and had been intercepting and hiding the regular letters Hawk had written to him, Mike who is stunned by his grandfather's deceptions, gets himself to Las Vegas to find Hawk.
Split into simpler sentences: Cutler did everything possible to drive his parents apart and had been intercepting and hiding the regular letters Hawk had written to him. Stunned by his grandfather's deceptions, Mike runs away to Las Vegas to find Hawk.