I like this the most. I will need some time to think on it more though. It feels ripe for Airships honestly. I did something a bit similar in a campaign in the past. Mountain ranges ruled by the Dwarves. They hold a lot of sway in the world due to owning the only mine rich in a mineral referred to as Float (a Material essential to airship travel and construction). Some of the mountains were still visibly rich with the stuff causing chunks of land to float gently in the sky. Sometimes rife with bandits set to ambush unfamiliar ships sailing the skies.
Hmm, that makes me wonder how the Gravity wells would play with an Airship, if I decide to include them. Seems like it would be important to avoid certain paths, otherwise the ship might get grounded, or smashed depending on the physics of the ship.