You can start this achievement near the beginning of the game. You can start this when
You will be given the quest Lazarus Rising in which you must find 4 car parts. After you give him the parts walk away for a few minutes and do a quest or kill some zombies while he is repairing your truck. Return and your truck will be ready. Get in your truck and drive up and down the roads. As you are driving around you will notice a progression counter that shows up after you make 1000 kilometers. Just enjoy the game, do some quests and it should come naturally as you are driving back and forth.