I never thought of it before, but probably the best thing would be to get 1-3 large floor exercise mats, the ones about an inch thick.
1) They would probably be cheaper than a bunch of pool noodles. In the image, just the BACK has 6 noodles. That's JUST the first blue to the second red.
2) Probably easier to transport and store.
3) MUCH easier to install.
4) There's a good chance the pool noodles wouldn't be the correct length to cover the car.
5) The noodles still leave the sides exposed, including the windows.