Progress on my Airship Fueling Painting

Now I've completed the fueling port structure and the dwellings on the right in my Airship Fueling painting. I'm trying to keep the colors in the low-value range to lend a post-apocalyptic tone to the painting. Its not natural for my work to have a grim, post-apocalyptic tone since I'm from the wacky Mad Magazine school of art. 

If I would have been working traditionally, I would have had to scrap the painting and start over. Three of the horizontal support planks along the bottom of the fueling platform were straight horizontal, which threw off the perspective. Somehow I missed this oversight in the preliminary sketch. But I was able to cut them out in Photoshop and slant them upward, and seamlessly repair the perspective error.

Next I'll paint the structures in the bottom center, then the airships in the background. I'll leave the "centerpiece", the foreground airship for last. I still haven't figured out what I'm going to put on the fuel tank in the upper left. Still open for suggestions.