Tips for Growing Pumpkins in a Community Garden Plot?

I'm excited to get an extra 8'x20' plot in my community garden this year, and I'm planning to grow pumpkins! They seem high-yielding and easy to store, plus I think they won't require too much maintenance for the space they take up. I'm aiming to plant two hills along the long side of the plot, with each hill about 6.7 feet from the ends and 4 feet from the sides. I'll be heavily amending the soil with compost and using cut-up garbage bags to warm the soil and keep weeds at bay. I also plan to mulch the rest of the bed with hay or cardboard. I'm considering planting Dickinson pumpkins or similar varieties, with the goal of getting my transplants in the ground by late May. I would love any advice on my plans, particularly regarding spacing and pruning.