My first 72 hour tf2 jam and also my first payload map, Breakwater Bay is a single stage payload map that runs through a small harbor and spirals into the red teams base. Planning on giving this a a combination theme of "Frontline" and "Bullet Crops"
A Boojum Snarks Ultimate Mapping Resource Pack: really helped me speed of my mapping
Also I used pl_badwater's sky texture and light settings according to the developer wiki:
I also plan or have already imported models from the frontline and bullet crops projects, all models made by their respected creators