Complex sentence: In his early teens he spent a year with a traveling tent show as a blackface singer, but by his late teens he left music and found work in the Texas oilfields, and in Missouri, Kansas, and Colorado as a farmhand and mechanic.
Split into simpler sentences: In his early teens he spent a year with a traveling tent show as a blackface singer. By his late teens he left music and found work in the Texas oilfields, and in Missouri, Kansas, and Colorado as a farmhand and mechanic.