Let me show you an eample of how my random city-centred sandbox can be used.
First, I assume the city has been generated and named according to the instructions.
Second, I roll 2D8 to place the waterway. I roll 3 and 7. There is a river flowing though the side, and I replace the road segment in square No.7 with a river segment.
Third, let us assume the adventurers leave the city by the southern gate. I roll 1D4 to populate square No.7, rolling a 2: there is a road that intersects the river.
The adventurers take the road eastwards. I roll 1D4 to populate square No.8, rolling a 3: there are orchards.
The adventurers continue eastwards. I roll 1D4+1 to populate te following square, rolling a 4: 4+1=5— I must roll on Table B. I roll 1D6, rolling a 5: there is a cavern.
You get the idea 🙂