I reiterate all of the above about rest stops--stop at each one but make em quick (then you're all stocked up in case you miss a stop--it happens). On my first century, at the last stop, they were out of water and only had blue gatorade! BIL later threw away that water bottle--couldn't get the berry blue flavor out!
I'm celiac, so I carried most of the nourishment that I needed in a small handlebar bag (now i use bento and jersey pockets). Anything I found at rest stops I could eat was a bonus.
We also zip tie a tire under the seat or onto frame--don't want to risk waiting for the sag wagon on your big day!
"Well-behaved women seldom make history." --Laurel Thatcher Ulrich
'09 Trek WSD 2.1 with a Brooks B-68 saddle
'11 Trek WSD Madone 5.2 with Brooks B-17