Return of the Rio Kid — Brett Halliday

An outlaw gunslinger begins the journey home to clear his name

A lone rider stops at the border, preparing to return to the United States for the first time in three years. When he left for Mexico, the Rio Kid was eighteen, a terrified youngster fleeing a fraudulent murder charge. He returns a grown man, with blood on his hands and twin .45s on his hips. His destination is a small town in Arizona, where he plans to clear his name and reclaim his legacy. But there is a lot of trail between here and there, with many dangerous twists and turns along the way.
 
Wanted signs paper every border town, offering $10,000 for the Rio Kid -- dead or alive. At his first stop on the journey home, the Kid is mistaken for a hired assassin and a Texas Ranger. To continue on his way, he will have to escape the clutches of a crooked rancher and the toughest lawman in the Southwest.
 
Return of the Rio Kid is the 1st book in the Rio Kid Adventures, but you may enjoy reading the series in any order.