You can best get this on the mission Uplift Reserve. Just beeline to the warthog at the start, and drive the entire mission. it's fairly straight forward with a few tricky spots. You can die, so there's no pressure to get things perfect.
- Make sure to know the mission before hand so you know the driving route.
- You'll want to 'rush and rest'. Go full throttle through enemy occupied areas, but stop frequently when not under pressure to replenish stamina.
- Make sure to get both marines on board when you first get on the warthog, it's tricky with the nearby enemies but necessary.
- At the main building about half way through, you can switch out your warthog and pick up a health pack. You can even use this as a chance to give your passenger the spartan laser for a little more firepower.