Maps and time lines, etc.

I've often seen and used maps contained in the front matter of a book. Also family trees. But never time lines. I've written one series of sci/fi that needed a family tree, but the one I'm working on now covers centuries and is all over the galaxy. It may need both maps and time lines! I sometimes have one of the main characters telling another the background of what is about to happen and I'm thinking about having character A draw a map or time line and having it at the beginning of a chapter, even if that ends up being the middle of the book. Any thoughts?

Maps and time lines, etc.