What you might try is tracking the top left and right corners of the truck and then track the 2nd black notch down the back of the truck as the bottom right and then the top of the door as the bottom left point, then move the track point + curson to the bottom corner of the truck side for the 2 points just above.
Basically this will allow you to track points that seem to stay in frame and create point data for the correct points for the corner pin effect.
Let me know if this makes sense,
Andrew