I keep a few pieces of veneer from other boat projects handy for just such a crack. The veneer can be cut almost hair thin and stuffed into the crack. A little furniture crayon the right color, and it looks OK. I wouldn't want to do it in the middle of a bulkhead, but in a less visible spot, it may be the easy fix. On Krogens, the inside of the closets are often finished the same as any veneer on the boat. You may be able to find a small sliver under a piece of molding. Some of us have taken whole panels out the the closets and replaced them with formica or cedar. But matching the grain pattern........good luck.