So as many as of you know, this achievement is a pain in the ball. Now there is a video on Youtube that explains to get the achievement, you need to start at Hueca, and drive to the bridge where there is two waterfalls. Then with practice, using the stairs of the vehicle as a starting ramp, jump on the ball and roll with it. After trying it out, and failing at being able to do it in one go, I discovered an easier way to balance and get the distance you want in less the effort.

You just basically need a long enough flat area and a way to get on the ball. Once you are on top of the ball, put yourself near the edge of where you want to go, then while facing the ball, jump slightly backwards and pull the ball towards you for just a second. Then land back on the ball and roll the distance with it. This way, the ball will go slow enough for you to stay on and once its stops, just repeat until you get the achievement. :)

Happy Hunting