I have a steel stomach, and I realize not everyone does, but my favorite for long rides is plenty of water or fake lemonade and a pb&j sandwich or two, and maybe an apple in pieces. For me, a pb&j sandwich just tastes perfect, and I like a few minutes off the bike to eat as a break when my feet start falling asleep.

I tend to want more protein ahead of time than other folks sound like they like. It also helps me if I drink a fair bit before heading out.