Typically when I run a Gamma World-style game, I set it up somewhere that I’m familiar with, and then try to extrapolate what it might be like after the end. However, I decided to take a shot at creating a sandbox-style environment for a Gamma World game (and to try my hand at large hex mapping for the first time in decades), and pulled out the 1e AD&D DMG.
Appendix B in the DMG (page 173) is a random wilderness generator, designed to work at a scale of 1 or 2 miles per hex. I ran it as-is initially, and as I was mapping I decided to replace deserts with radlands (so a few of the radlands on the map also have desert indicators that I drew in first, oh well). The ruins results on the Settlement table have to be re-thought slightly – replacing Shrine and Tomb with other ruins of the ancients.
The only other change needed really is to change the definition of a castle, and then to go to the Castle Tables in appendix C and see if they need any changing. In the end I decided to live with them as-is also, just to remember to implement elements of post-apocalyptic civilization in them (so many fortresses are actually built up around ancient ruins that withstood the wars and destruction).
So, after 20 minutes of dice rolling, and then an hour of map-drawing, here’s my Instant Wasteland.
The squares on the map are “castles” according to the random generator. These are armed outposts of one group or another of wasteland survivors (or possibly ancient robots and AIs). The two skull and crossbone locations are ruined shrines or tombs according to the generator – these are classic Gamma World dungeon environments – research station, AI-run arcologies, or whatever interesting “dungeon” you have laying about. Finally in the swamp to the North (by College Fortress) and in the scrublands to the SouthEast (near Braferd Mills) we have a pair of ruined cities of the ancients – also great places to hunt for adventure.