Here's the latest Kelp Side design for the Birch Aquarium outreach van. It's vastly simplified from previous designs, where I felt I had to put in as much kelp as possible. I might put in one more, and maybe some green shadows to suggest kelp in the distance, but I realized that I don't need to take kelp forest so literally. Note that none of the design, aside from the blue water wraps around the corners of the van. This will make things a lot easier.
Resolution is funny. If say a fish image is printed really small, then it's OK if it's low resolution, like 100 dpi. At medium (letter) or large (poster) size it does matter, because people will notice the pixelation, so 300 dpi is good. But once you get up to ginormous size, ie van size, resolution can go down again because people generally only view the van from far away, and can't make out the resolution. Thus the van image is 100-150 dpi.