Well I have started on my S&W sandbox setting.
The little barony far far in the western frontier. First of all the walled city of Raven's Keep came out really well. It is a city of around 8000 (or more) people. I placed it in the middle of the map with a road going back to the eastern kingdom. The western road comes out and joins a north south road.
It is well know that the city was founded long ago but the history is very mysterious. The most popular story is the city was founded because of a wellspring. A never ending wellspring that gives the entire city running water unless the cold freezes it. The water drains down to an ancient sewer that depths are unknown. The city is surrounded by bountiful fields that are are watered by the wellspring.
The oldest and most poplar religion of the people is of the Grain Goddess Keres. The city will live and breath the ancient festivals dominated by this goddess including one inspired by the original 70s movie The Wicker Man. There are other churches as well. A few will be written by the players.
The scale is rather small. One inch equal five miles. On an 8.5 x 11 inch piece of paper not a large setting but I have packed this page with lots of possibilities.
There are two dungeons the simple Bloodrock Castle and The Black Stairs less than a day away.