Very nice work! It's always good to have another way of looking at things. Many people use the Map Inspect feature of BOB to get this kind of information, but it is icon-oriented, which has its pluses and minuses (less likely to overlap, but not as obvious as linear connections), and not everyone can use BOB (which requires Greasemonkey and Firefox, or possibly the Chrome browser). These diagrams are available to all who have a browser.
Queen_Herpes will thank you.
There was a tool once that would draw lines directly on the maps, but the link was broken last time I checked.