---

Take the train between cities.

The train line in the game is represented by the red line on the minimap. There are stations scattered throughout the game, but they arent represented by an icon on the map. In order to unlock the trophy you need to travel between two cities on the train, either as a passenger or as the driver. It is much quicker as a passenger as you can skip the entire journey by pressing (X). I unlocked the trophy by getting the train from Cranberry Station at San Fierro and then skipping to the next station. Just hang at the train station until the train pulls up, and then press (triangle) to enter it, as you would with any other vehicle.

The below video shows the exact location of Cranberry Station and how to unlock this trophy: