I'm presently trying to set up an Underdark area for my campaign. I'm wondering how to do it. Primarily the map. I do have the D1 module, but I'm not sure how well the map there will serve as a model, since I'm using a 5 mile per hex map for the surface and I want the two maps to line up. If I used D1 as an example each hex should have multiple tunnels running through them.