Liza, be warned Pumpkins take up A LOT of room. Same for watermelon. Pumpkin vines and leaves get huge. Same for any of those vining type winter squashes. However they are very rewarding to grow. I think you have lots more room there in your backyard. These might be future crops for you when you expand your veggie garden.
And not to worry too much about the water. Lots of us just water with the hose. Also a soaker hose would be easy to lay and can just stay put in location permanently.
