This was my first attempt at blowing up the scale of a boardgame, so my choice of materials was somewhat questionable. But, here goes: I glued several layers of corrogated cardboard together to make the board (but I now usually use the craft board that has a 1/4" layer of styrofoam between two sheets of posterboard), cut the lines for tiles and for the numbers within the tiles with a razor blade and then used a ball-point pen [very high tech] to force the lines to stand out more by pressing quite hard. Cut out the top layer of the cardboard from the locations that are impassible so that they could be used to mount the various scenery products and allow the game to fold up into a compact shape (important when you drive a small car). Spray painted the entire board and the removed pieces with the fake-stone paint that you can get from any hardware store. Used a dark black wash to bring out the squares and the numbers. Made the railing around the open shaft by glueing skewers. After that, it was finding/modifying/creating miniature to go with the game.
