Complex sentence: Mark proceeded to do many ABC tv shows and feature films, until he decided to walk away from the industry to raise his three daughters in the Mountains, during this time he wrote two feature film scripts and was composing music.
Split into simpler sentences: Mark proceeded to do many ABC tv shows and feature films, until he decided to walk away from the industry to raise his three daughters in the Mountains. During this time he wrote two feature film scripts and was composing music.