Weird Krypton

Strange is the night where black stars rise,

And strange moons circle through the skies,

But stranger still is

Lost Krypton.

Superman's home planet is pretty weird. Weird enough that it makes a good substitute for Carcosa in McKinney's supplement. You can keep the polychromatic humanity (that might explain the Krytonian flag). Then, check out the maps of Krypton for places to visit:

The highlights there ought to be pretty obvious, but let me fill in a couple of salient points of adventure and/or danger:

Jewel Mountains: Formed by the accumulated carcasses of prehistoric, giant crystal birds.
Gold Volcano: It should be mentioned that gold is so common on Krypton as to not be particularly valuable.
Fire Falls: A fall of a fiery fluid from the planets core, inhabited by mutant fish-snakes whose bite is poisonous.
Scarlet Jungle: An expanse of forest in red and purple, including huge maroon mushroom-like growth. It home to at least some disease-causing spores. Then,  of course, there's the herd migratory, vaguely humanoid-shaped plants.