I try not to overthink this stuff. And there is a lot of "different strokes for different folks" that applies. OP didn't define "long ride" so for me it's 40-60 miles. Last two Saturdays I've ridden over 50 miles. I don't usually preplan what I eat in preparation for a typical ride, but if I'm going out early right at sunrise, I don't want to fill up with a big breakfast. Two pieces of toast with peanut butter and honey, (bagel with PB is good too), cup of yogurt, banana, a few Medjool dates, and a couple cups of coffee. When riding, a PBJ and/or Dates, sometimes a Clif bar goes along. I don't require a LOT of food for that distance. Maybe 6-8 dates or a Cliff bar, maybe throw in a Little Debbie or Twinkie.
The Medjool dates is something I've only recently discovered, they are little energy bombs! And if you want some rocket fuel, mix a couple big spoons of raw honey in your water bottle along with a Nuun tablet. That stuff will keep you going.