I like the functional map idea too. I would suggest doing the maps as you have done here, then do some stressing of the lines once all said and done. That would create that chalky feel and age the map, but those kinds of things are usually done near the end of the work. I also like Eochiad's idea about having it be an older map that had a few notes and stuff. I always thought that Dwarves took care of things and would hand things like this down from generation to generation. Nothing wrong for players to receive some misinformation Just make sure to keep a GOOD copy for yourself

Keep it up. I think you are doing great here