As my introduction to the SDK I decided to make a ZOC mod.
Forgive me if this exact thing has been done before, I just didn't see it anywhere.
This mod doesn't block movement in zones of control, it just prevents units from using any roads/railroads while in ZoC
Specifically, when your unit moves from a land plot next to an enemy unit on a land plot into another plot next to an enemy unit on a land plot it does not gain any movement bonus from any road/railroad present unless the unit has the commando promotion.
I think that this emulates the requirement of forces in contact with an enemy to deploy into combat formations that do not allow efficient use of roads or railroads.
In undeveloped areas this will have very little effect, as it only removes the effects of routes. It will however, have a greater effect later in the game when all or most of the terrain has roads/railroads.
This mod currently is for Vanilla only, as I havn't set up warlords for compiling yet.
AA's ZoC mod 2016-10-05
AA's ZoC mod