Well the trunk board is masonite and can be found at Home Depot, but in just larger sheets that would have to be cut down. The simplest way to do things is just go to a junk yard and get whatever you need there. The cost will actually be cheaper to get the carpet and board there over anywhere else. I know with my Accord too that the carpet runs all the way to the top of the backside of my backseat, so replacing the carpet could be somewhat complicated.