Hard to beat peanut butter. It's somewhere around 165 calories per ounce. It's also easy to pack and doesn't really spoil. It also hits the spot when you have a salt craving. I would plan most of my meals around it. You have different PB delivery methods- tortillas, crackers, oats, etc.
I'm riding across the US south to north in June and there are days when I'll want to carry 2-3 days' worth of food. I think that will mainly be peanut butter, tortillas, oats, dried fruit, and Clif Bars. I'll be close to civilization most of the time, but I'm not big on eating out and I don't want to spend more time shopping than I have to.