I'd also include a small notebook for making notes or drawing designs you like. You are supposed to ask before you take pictures, esp in the vendor areas. I drew some designs that I saw to keep in my scrapbook.
If you can, buy some sturdy cushioned socks. I got some from REI as when I was at Paducah I put holes in my socks from all the wonderful walking.
Since I am from Arizona, YES to a water bottle. However, I take a very little one so I can easily refill it at the water fountains and it weighs less than the bigger bottles.
ali