Professional Postman
40 GS
Find and complete all of the Pony Express side missions.

For the Pony Express missions, all you need to do is reach each destination within the given time limit, they are easy, just make sure not to kill your horse but spurring it too much. There are ten missions in total, six in Dodge City and four in Empire City, to start press the Y missions press to talk to either Earl in Dodge City or Daryl in Empire City. Once you complete them all the achievement is yours.