Hitchhiking is the fastest, cheapest and easiest option for locals and visitors in the area. The main hitchiking hub is in the southern exit from Jerusalem, a place called "Tzomet HaMinharot". Any time between 6am and 1am, you're likely to be picked up by a Kippa-wearing, smiling nice guy which will take you for this 12-20 minutes ride. Good points to go to are Tzomet HaGush Gush Etzion Junction or Efrat Darom southern entrance to Efrat.
Another option is to take the bullet-proof Egged buses. Leaving from central station in Jerusalem, lines 160, 161 and 164 leave every 30-60 minutes for Kiryat Arba get down in Tzomet HaGush, Efrat and other settlements in the area. They are also stopping in the far side of Tzomet HaMinharot- don't forget to wave the driver!
