Oh my yes, like having an ice cube on the back :D
I have considered putting loose things like pretzels in a Bento box so I can just reach in from time to time for something salty when I need it. I am more resistant to stopping when I clip in for some odd reason...
Ruby, you are going to have fun working out what works best for your body - in the end that is the most important. Have fun on your long ride and let us know how it goes! I would suggest hydrating well the day before your ride if it is going to be hot.

