I never stop on a century ride, it's too short for a stop. You can drink and eat while riding that's not difficult.
If the ride is supported you will have water bottles handed to you without stopping to get it; if it's unsupported you can carry at least 2 bottles on your bike with an optional third by using Minoura brackets; and you can use a CamelBack with either 70 or 100oz, but don't go over 100 or the weight could make your back hurt after awhile.
On long rides I carry 3 24 ounce bottles and a 70 ounce Camelback and haven't had to stop to refill even in the summer heat of the Mojave Desert in Southern California where I use to live. Only on longer rides where I've gone over 150 miles did I stop about half way in some town to get more water and food. If you do have to stop, stop for very short times of no more then 10 minutes; anything longer then that and you legs will feel heavy or tired for about 20 minutes after you start riding again.
Gatorade is a very good dring to take on Centuries BUT you need to dilute it at least 50% from recommended useage. I don't eat one meal half way through, I'm eating small amounts of food during the whole ride. I've found that eating a larger meal instead of many smaller ones made me feel like I had less energy; and according to a sport coach I spoke to (many years ago), a larger meal makes you feel tired because it loads your stomach with food which it then has to exert energy to digest it taking energy from your riding to do it thus lowering your performance...but that was old science maybe they discovered that's not true now, but I know I was more tired after eating larger meals.