RED RUINS: Far-Future Post-Apocalyptic Science-Fantasy Mars

Everybody loves science-fantasy post-apocalyptica. A campaign setting where humankind is dwelling amongst the ruined planet-hopping civilization of a terraformed Mars is right up my personal alley. Setting a campaign on Mars allows for some interesting geography and the ruins of terraforming machinery. I've been writing notes and encounters for this setting for years. I call it Red Ruins. 

I have run two one-shot sessions in this world, both using different hacks: one using a one-page RPG called BLASTER, and one using my own combo hack of Ben Milton's Knave and Maze Rats—Maze Knaves. If I ran it again for a new group I might use Into the Odd with a new table of starting equipment flavoured for the setting. 

The fiction that inspired this setting includes films such as Nausicaa of the Valley of the Wind and Mad Max, and books like Stephen King's The Dark Tower and Kim Stanley Robinson's Mars Trilogy. Also the incredible RPG Numenera by Monte Cook Games, which is a great game in which the GM can really just make up anything they want, and there does not need to be a setting-consistent explanation. 

Here is some flavour text I wrote for the players to read before my last one-shot:

You live on Mars. In ancient times humankind settled the solar system, with technology so advanced it might as well have been magic. But a very long time ago something happened back on old Earth. Spaceships stopped landing, communications satellites crashed, and generations of famine, floods, and freezes pushed the red planet into a dark age. With old knowledge lost, technology has truly become magic. Mars today is a strange place full of strange things. Knights riding giant rabbits fight with swords. Mutant pig-people ride motorcycles through southern dust storms. Electric wizards live in glass towers and study ancient secrets. Trees a thousand feet tall sway in the low gravity. Cowboys herd lizard cattle through dry mountain passes. A thousand gods have shrines dotted around the dusty landscape. Red ruins of silent stone wait in the wilderness, full of treasure and danger. Mars is a beautiful place.

Here are 20 encounter ideas/plot hooks/adventure seeds for the setting:

1. Ancient stairs are cut into a tall mesa; a glimmering yellow light can be seen up top. It's a seasonal camp for glider pilots scouting mine claims from the sky. They could use your help to ground-truth some aerial photography. 
2. An old patriarch in control of an irrigation dam has gone nuts and is cutting farmers irrigation supply for the smallest infraction. He's barricaded himself in the dam with his family. 
3. There is a ghost town along the Northern Ocean that is only accessible by gondola. It is full of friendly ghosts who try to get you to eat the food and therefore turn into a ghost also. 
4. Señor Saguaro is a cactus ent who invites you for tacos in his cactus cave. His lithe husband is a sexy flower boy. He warns of giant burrowing owls that nest in the ground up ahead. 
5. You must climb down the cliffs of the Valles Marineris—the deepest canyon in the solar system. 
6. There's a gang of genial pirates driving a trash bus. They are searching for a relic which was prophesied to them by their grandparents. It will bring fresh water back to Mars. 
7. Some power priests living inside an ancient power plant have discovered a weird vat of nanobots. Submerging one's arm in the vat totally dissolves the flesh but replaces the arm with a strong and self-healing tentacle thing. About half the priests have done this to one arm, a couple to both, one guy from the waist down. The most radical priest is planning on dipping his head into the vat and they're having a ceremony.
8. A chance comes to steal some mega-olive oil from the pig-people. The pig-people tend the mega-olive groves to distill oil to fuel their motorcycles, and are generally real assholes to everyone else. 
9. Prakon Lyons the bearded drunkard has found a laser sword and is challenging people to duels. 
10. Two creepy sets of triplets are planning on fighting a gun duel (a sextual?) to the death. It has been scheduled for noon tomorrow, but somebody said that both sets of triplets are already starting in-fighting about who is designated as whose 'second.' 
11. Somehow a child has gotten stuck on the tiny island in the middle of the poison lake. 
12. You come upon a group of adventurers camped outside a ruined reserach complex. They are planning on entering the complex to find rumoured treasures of bio-engineered plants in glass vessels which can feed an entire village for a year. They all wear masks and appear to be breathing heavily—they refuse to take off the masks but politely ask for water for their mounts. 
13. Coyotes with no lower jaw begin stalking you at dusk. They're easily spotted but wily and slip away each time. Their tongues grow longer and more furious each time they're spotted. 
14. You find a boiling hot stream—following it upstream leads to the overflowing drainage pool of a nuclear power plant blasting along full power. 
15. Six women roar up on stolen pig-person motorcycles. They try sticking you up for your valuables. They have pretty small arms, and if pressed admit to having limited fuel supplies.
16. A hunting shack is found devoid of life; sausages and other cured meats hang from the ceiling. Later on the road you run into a hunter, her daughter, and their three dogs prowling for bison and bear. They are nice but turn hostile if they spot stolen sausages. 
17. A flock of great roadrunners zings by chasing a coyote. They catch it and tear its flesh horrifically; they turn around and spot you with a crazed look in their eyes. If butchered after defeat their brains are covered in a terrifying black fungus that pulses and throbs, reaching out towards your brain. 
18. A lone farmhouse has a recently murdered corpse just outside it. There are a dozen freshly turned bits of soil in the yard. If exhumed it reveals a dozen large clay pots of fermenting cabbage—delicious and nutritious. The murderers return shortly with a wagon and two mules, to cart off the kimchi. They will fight youfyou it.
19. You meet some friendly dirty youths in a garbage dump who invite you to go “tubing.” This tubing ends up being digging around in old junk heaps for ancient vacuum tubes so that they can try to get an ancient computer going. They say that their great-aunt uploaded her brain to it before she got eaten by a colossal condor. 
20. A sick woman has a throbbing purple jewel growing from her gums. It hurts and she’s desperate for assistance. Reluctantly, she reveals that she got her fortune told by a fortune teller, didn’t like the rest, and refused to pay. She thinks maybe she got cursed.