Some rough thoughts on what might go into a post-apocalyptic game using FiveCore:
An Apocalypse generator (this will basically let you roll up a random setting, including what nature the apocalypse took, follow on effects and how long it's been)
Some apoc specific character generation options.
Rules on foraging, wilderness campaigns and food/water/medicine.
Tables to generate: encounters, enclaves, cults and societies, political factions.
Random event tables for campaigns more focused on survival, maintenance and endurance.
Maybe hit somewhere in the 30 page range? Longer than a typical FiveCore supplement but not big enough to be a fully fledged game on its own.
My thinking is to focus a little more on the more human and "realistic" side of a post-apoc environment. People can use the alien traits from Five Parsecs to generate mutants and whatnot though I suppose adding in a "mutant generator" might not be a terrible thing. Thoughts?
Also will need a snappy title with "five" in there somehow. "Five days after the end" ?