Turn based 2d star ship movement

This question is has several parts to it about star ship movement and how to program them. I want to show the possible movement 'cone' for a ship before it moves, such that a opaque cone in front, and if the ship has enough bow thrust, backward.

I figure that rigidbody will be used for the ship, which I could give actual mass to and apply force to the stern, starboard, port and bow, and then figure out torque based on that to turn the ship. Now, what would be the most efficient way to show the possible move to locations? I assume showing all the points would be pretty processor heavy. would finding the edges be best? put one thrust vector to full and increment the others, looping through all 4, and then draw a line between the points? I also have no idea how to do run time animation or shape making like that.

If this question, not having any code, needs to be somewhere else let me know. Thanks!