On this week's 1000k, I stopped at a store selling fried ham sandwiches. Not a great source of carbs, and I couldn't eat much at a time, but it was a really good supply of salt. I have had good luck with convenience store cooking, I remember one cheese steak and fries that kept me going for 100 miles. I was having trouble deciding what to eat and then I realized that everyone on both sides of the food counter could stand to lose some weight. So decision made! I had been looking for frozen burritos, which are pretty good food on a long ride.
I have started eating packaged ice cream cones. I'm not sure there is any dairy in them. The cones themselves have a fairly high number of calories, even ignoring whatever ice cream substitute they are holding.
I have had good luck with cups of noodles. More of a nighttime food in the summer.