A route follows a land graph
Each cell connects to its up, down, left and right land neighbors. Water cannot be crossed. The search chooses the smallest accumulated terrain cost, which can favor a longer plain route over a shorter mountain crossing.
The cost of an edge averages the two cell terrain multipliers. Plains use one, forests one-and-a-half and mountains two-and-a-half. These are declared game conventions, not measurements of real terrain.
Separate steps from weighted effort
Distance is the number of orthogonal steps multiplied by kilometers per cell. Weighted distance also includes terrain multipliers. Dividing weighted distance by four produces the displayed fictional travel hours.
The route ledger records both the distance and the stated timing assumption. It does not model rests, supplies, weather, encounters, elevation, roads or individual character abilities. Those decisions remain with the game.
Review after a terrain edit
Routes are recalculated from their endpoint locations. A new water barrier may disconnect them; moving a location can change the path. Unreachable routes remain in the editor’s list with an explanation and are omitted from the map drawing.
Do not treat an absent line as an unnoticed successful route. Inspect the disconnected count before preparing handouts, then decide whether to change the terrain, move a place or handle a crossing explicitly in the game.