Before the web, when gamers were on the newsgroups (1990), a bunch of us on rec.games.frp got reinvigorated about an old game called Gamma World (GW) and started posting things again. For my part, I dug up an old supersector generator (a supersector is 144×144 km.). I had built it for my GW campaign around 1978-1979 because my characters started scurrying all over the countryside and I needed to know what was in between the adventures. This system worked pretty well. It would be pretty easy to build a map generator from the charts, so if anyone does that, please let me know. The Official GW Map from 1st edition is online as well, but I really wasn’t paying attention to that. The image to the right is a great web comic that reminds me of Gamma World and Jack Kirby’s Kamandi comics.
PS: Here’s an update from 2016 — I’ve now taken the old map generator and created a GW Supersector generator. I added in generators for creatures, mutations, treasures, and cryptic alliances, among other things. I’m not distributing it yet; just wanted to let you know what’s happening with it now!
PPS: In 2017, I was preparing to run a Gamma World campaign and mutated the system and world enough to call it Mutant World. You can see that stuff at https://lostdelights.wordpress.com/category/mutant-world-campaign/