You might think my timing is odd since it's three years later and the thing is at the end of its print run. That's true, but today I came across the information that McKinney is close to half-way finished a companion to the first Carcosa book that has a bit more detail on how the world of Carcosa works. He still has it arranged as a hex crawl, he's just providing a lot more information in each hex. All of that information together would allow the GM and players moving chacters through them to build a better picture of how life on Carcosa actually works.
This new development got me thinking again about what I wanted to do with this book that I've had on my shelf for a few years now.
Carcosa is an awful place full of amoral peoples, cultures and creatures. It's a cruel, nasty world that is moved by horrific rituals and covered with dinosaurs and shambling creatures out of H.P. Lovecraft's nightmares. It should be a something of a shock to players who are used to more traditional fantasy and science fiction settings. I think that's where the fun of the setting can be found and developed.
I think the best party to have in Carcosa would be explorers from our world or a close approximation of it. The first time I read this book I thought it would be cool to trap a team from earth in it like the film Stargate. A team of specialists from modern times (anywhere from WWI era to right now) could go through an ancient gate to the world of Carcosa. The timing for this trip would be bad and they would enter during some kind of event that destroys the gate on the Carcosa side before they can figure out how to return through it. Now the party has a simple goal: Find a way home. They could chase rumours and technology all across the map.
Since attrition is a natural part of the game and the Player Characters from earth would need to be replaced by locals when they died, the party that finally found the gate back to earth might be entirely Carcosan. It's only natural that the party would find locals to help them as guides and translators. These people would naturally want to leave Carcosa for the amazing land of Earth where they need not live in fear of terrible creatures or dying as a sacrifice in some horrific summoning ritual. A place where food is plentiful and people live and work together in what would seem insane luxury would be an impossible dream for the humans of Carcosa. I picture what would eventually become a party of mixed-colour Carcosans speaking English and wearing bits of earth-made kit as they cross Carcosa looking for clues to get to the promised land.
I'd play everything in Carcosa pretty much as it is written. I'd even use all the nutty dice conventions, at least for a while. I'd have everyone roll for psionics the first time they encounter a minion of the old ones like a shoggoth or a psionic-using creature. That's the easy part. My biggest decision would be deciding on a system to use and the modifications to the classes for their modern interpretations.
I've thought it through with the Lamentations of the Flame Princess: Weird Fantasy RPG System. For anyone unfamiliar with LotFP, it's a D20 RPG based on the Basic/Expert books of the early 80s with some innovations and changes that push the tone of the game towards exploration of the unknown and horror. Carcosa is designed to be played with those rules so it would be fairly easy to have a group roll up a bunch of appropriate fighters and specialists. I'm playing a lot of 5e D&D lately though, and I can see how well the conventions in the Carcosa rules could work with 5e D&D. It is tempting to make some adjustments and use the new D&D rules to play. NOTE: at the time I'm writing this post the 5e DM's guide is not yet available. It may have advice on running in a modern setting like earlier versions did.
Making a list of kit that everyone has like E-Tools (folding shovels), canteens and ration packs is not a big deal. It could even be fun since things like solar charging units and laptops are not out of the question. Firearms need to be addressed though.
The firearms rules in LotFP could be adjusted for faster rates of fire and loading. For automatic weapons a long burst (full mag, minimum 20 rounds) could do two dice damage in a cone area of affect with a save verses devices for half. A short (or long for that matter) burst on an individual could add +1 to hit for every round used beyond the first. So holding the trigger down for a five-round burst would get a +4 attack bonus. This would need to be declared before the roll to hit. Anyone other than a fighter would a die six and add the even number rolled divided by two and subtract the odd number rolled to the desired amount of rounds used. For 5e the long burst as a cone would work the same but the short burst on a single target would be 3-5 rounds (D3+2) and would give the attacker Advantage on the roll to hit. Grenades could just use the Carcosa grenade rules. I'd give everyone five full 30-round clips and maybe include a box or two of ammo for the group.
The thing I like about 5e in Carcosa is the healing in 5e is based on Hit Dice. That means players could recover lost Hit Dice after a rest and have them to roll for the next encounter. It just fits so elegantly into the system and solves the problem of healing slowing down a party in Carcosa. The unpredictable dice conventions of Carcosa and general lethality of 5e mean the stakes in any given fight will be high regardless.
The players would need to build a team. Such a group would be hand-picked for certain skills and trained together as a unit. The fact that they would likely have an expert on antiquities/ancient technology/cultures/myth since such a person might have been needed to get the gate up and running in the first place means the modern party could contain a wizard. Everyone would be human. In 5e that means feats would be available so at least one of the party would need to take the feat that allows for extra languages and talent for linguistics (like Daniel Jackson in the aforementioned film Stargate). It's possible this character would be a 5e bard who is a lore specialist and would be included for the first contact team for cultural adaptation and communication. In LotFP it would just be a specialist with the languages skill. The team would also include a medic so LotFP could add the Medical skill to the specialist skills and the 5e player could take the Healer feat. A sniper in 5e is just an Assassin but in LotFP it could be a Specialist with Stealth, Sneak Attack and pips for +1 attack bonus with a rifle. A close-combat specialist would be a fighter in LotFP and possibly a monk in 5e.
Some classes for 5e would need to be removed. Paladins, Clerics and Druids just would not fit. Sorcerers, Rangers, Eldritch Knights and Arcane Tricksters also don't work well with the setting material, having no real place in either world. I'd remove them as well. Warlocks with an Old One as a patron fit well but the other patrons would not be available. In fact, I'd be tempted with a 5e game to remove the Carcosa Sorcerer class and rework the Pact of the Tome to be the ability to learn and cast the Carcosa list of rituals. That would mean all the NPC Sorcerers listed in the book would be Warlocks. Wizards could stay the same but would be extremely rare, super-scientist types.
It would make for a long and satisfying campaign. Especially if the party actually succeeds in returning to Earth with a pile of alien technology. Players could play in the gonzo sandbox that is Carcosa and I could ramp up the evil nature of the setting while the players played PCs with a positive value system totally out of whack with the world.