Complex sentence: The player and Rock must trade with Indians and find a safe passage to the Pacific Northwest, where they find Baron Grinnit hiding in a dugout canoe and arrest him for the second time.
Split into simpler sentences: The player and Rock must trade with Indians and find a safe passage to the Pacific Northwest. Upon their arrival to the Pacific Northwest, the player and Rock find Baron Grinnit hiding in a dugout canoe and arrest him for the second time.