I love the characters, Gene! Your style is really showing through in your modeling!
Here's a couple of materials I made when I was modeling the monkey ship that might be helpful to you with your ark model. The materials make it look like the surfaces are made up of boards. They are cartoony, but I think that will work well with your style, too.
Note the custom settings in the object groups. I give the materials negative bump percents and mess with the scale (to make the boards the right size.) Here's a super-simple model to show what they look like. The negative bump percent cuts the grooves into the surface. You can choose your own colors.Click to view attachment
Here's the zip. Sorry for the enormous size, but the deckpattern image I made is enormous.Click to view attachment