Complex sentence: In addition to his musical career, McKagan has established himself as a writer; he has written weekly columns on a wide variety of topics for SeattleWeekly.com, Playboy.com, and ESPN.com.
Split into simpler sentences: In addition to his musical career, McKagan has established himself as a writer. He has written weekly columns on a wide variety of topics for SeattleWeekly.com, Playboy.com, and ESPN.com.