I am aware of Bee's excellent map. --- I even get a mention in the credits
What Bee has done provides a good visual mod but loses the stock game functionality of road and rail, like auto placement when map building and auto tracking of the route by vehicles when mission building.
What may be needed is similar to what is in Clod, in that road and rail appear to be defined by freeform splines which then control the placement of road/rail plates and also control the vehicle movement, but that would require some serious coding input.