For me it’s sitting on top of the flat roof of a building at the side of the road, on the map at the right of the Descansar Dorado Sprint race icon, and just above the “C” in the name of the Costa Rocosa landmark, out where there’s exactly nothing nearby to jump from. In FH4, my last one was on the roof of the church, and later on in the game a danger sign ramp magically appeared at just the right place. Hasn’t happened here yet if it ever will.
Have you solved that one?
wrong answer, deleted
Went to the location tonight. Park in front of the house looking at the board then look off the right side by the silo and you’ll see a hill in the background. Use this hill to get air to land on the house. You’ll need about 100mph to reach the house.
The video link in the previous post has a video of someone completing this.
Did this one last night.
It’s one of the easiest 
Well, thanks, folks. Mission accomplished.
Never in my lifetime would I have thought about trying that ‘reset car position’ trick. I still feel a little bad about not trying to do it with a jump, but it’s done now. It’s not like that 200-credit charge for a fast travel was a budget-breaker, but it’s good to have finished the achievement.
So thanks again. I’ll see if I can figure out how to give you some kudos.