Complex sentence: Following the deaths of his wife and mother, he took time to grieve by escaping to the wilderness of the American West and operating a cattle ranch in the Dakotas for a time, before returning East to run unsuccessfully for Mayor of New York City in 1886.
Split into simpler sentences: Following the deaths of his wife and mother, he escaped to the wilderness and operated a cattle ranch in the Dakotas. He returned to run unsuccessfully for Mayor of New York City in 1886.