Gorgo

Real per-POI numbers from the game's own data: the default army strength and siege health a march would have to fight through at a crossing, bridge, tunnel, harbor, or seat along the route. This is each node's base/unclaimed garrison — not necessarily what a faction currently holding it has stationed there. Each slider is added cost per 20K power / 100K siege health — 0 ignores it, higher makes it more punishing.

Set what each level costs. 1 is an ordinary step; 10000 means only if there is no other way — the route still takes it rather than failing.

The fewest crossings, bridges, tunnels and harbors you would have to hold to keep an attacker out — water and mountains do the rest of the work, these are the doors through them.