Okay, just had a thorough look through all of the 14 maps.
If you want to join up all the sections together correctly so that the roads align, you will need 2x of each map, because the map stretches across both sides.
A lot of cutting and preparation is going be needed to get it accurate.
You could just get away with folding at the pre-folded parts to join up and just stick together which I think will be a lot more practical and easier. But you'll have a bunch of extra layers behind the entire thing but that can easily be cut away if desired.
Just ordered my second lot of maps. Will be doing this when they arrive. I'll post a photo when done. I believe all of it combined will be gigantic. So probably will need a ladder to even see certain areas, but it will be bloody cool.
Good project!