Bad Piggies Rise and Swine Level 2-20 can be 3-starred in two steps. Build a three frame motorized cart with the grappling hook above the first frame. Use the plunger to lift it up on the platform above. To beat the time trial, place the grappling hook on the middle frame. Guide your contraption all the way to the other end, and carefully send the plunger on the cliff to pull it up to the finish.
If you have a different strategy for completing this level feel free to leave a comment below.