Oil is available across many points in the South in various amounts. We are likely only talking about a handful of wells considering the scale of the world in the films. Which could literally be available in any of the Southern states. Poppies are a versatile crop and will grow pretty much anywhere with a summer…

I think it's intentional. Southern "Gentleman" (Plantation holders) are the closest thing the US has ever got to a recognizeable hereditary nobility. The setting also seems to be a post apocalyptic Southern US, possibly Louisiana/Mississippi area. The Badlands could refer to the more arid (as hinted in the last…