Bad Piggies Rise and Swine Level 2-19 can be 3-starred in two steps. Build a three frame motorized cart with the grappling hook above the first frame. Guide your contraption to the edge of the platform, and use the plunger to pull it up onto the star box. Then simply let it roll down to the finish line. To collect the second star, use the same contraption, and carefully let it fall into the crevasse. Then use the plunger to pull it up into the last crevasse.
If you have a different strategy for completing this level feel free to leave a comment below.