In “Road Map”, replace “the GPS should create and append to the list of Stops a new Stop with a Name of their choice” (in all instances where it appears) with:-

any Tripper (or the GPS) may create and append to the list of Stops a new Stop with a Name of “Darkness”

Add to the end of the rule:-

The GPS may rename a Stop named “Darkness” to a Name of their choice, at any time.

In “Stop Effects”, replace “When generating this stop the GPS must change the x” with:-

When this stop is generated, whoever generates it must change the x