Well I need some suggestions........

[parishht]

I think you are on the right track to make new boxes out of Starboard.
But, since it is not an area that is visible to the naked eye,
why not check out the new plastic lumbers at Home Depot?
They may end up being a lot cheaper than Starboard.

He77 if you remember, I replaced my rear hatches with left over plastisized deck boards.
Painted white with the plastic paints.