The achievement description pretty much tells you what you need to know.
There are several potential ways of unlocking this one, but it's not going to be super quick whichever way you go.
You will need to complete the career races in each area, in order to unlock a livery (blue) dopler truck and occasionally (purple) bonus vehicles. Chase down and collide with these to collect the bonus machines and unlock all of the livery points in that area (you will still need to travel to the actual point itself).
You will also gain liveries by buying vehicles if you want it quicker, but if you intend to get the 1000g, make sure you do some challenges to get your cash up, as the later machines are quite expensive compared to the early machines.
Once you have collided with the livery dopler truck, you can use the trick of creating a very short custom race with the end near the livery point, save and quit, then test the race and then go to freeride, this way you only have a short distance to travel, it speeds things up but will compromise the total distance driven in freeride achievements.
If however you are going for the full 1000g, then I would recommend getting dropped off at the nearest Helicopter point, as you will need to use them 100 times to get
then ride/drive to the destination as you will also need to rack up the mileage in freeride to get
The Globetrotter achievement in FUEL worth 101 pointsDrive a cumulative total of 620 mi (1000 km) in free ride mode.
the larger of the distance travelled achievments, you can also work towards getting 200 tricks and 500 oil barrels as you go.
I found that by using a good offroad bike (Valkyrie ideally) you can get close to where you need to go without coliding with too many trees etc, then to collect the livery points that are high up on the top of a mountain I switched to The Educator as it seemed really good at getting up steep slopes easily.