Making new partition for back seat/trunk area

I used some corrugated plastic to make interior walls for my 1st boat. Covered it with indoor/outdoor carpet.

72 in. x 36 in. x 5/32 in. Twinwall Plastic Sheet-COR-3672 - The Home Depot

I think that's what I'm looking for. RPMagoo aluminum would be the best way to go but probably more expensive and not as easy to work with, also my car isn't a race car. Well at least not for now lol. adriver I will take a look at the Masonite board as well see which one I like best when I can actually touch it and look at it in person.