hey, also coming late to the convo, but i did a bike tour down the coast of California last year and wanted to contribute from my experience.
for the first part of the trip i didn't have an alcohol stove - i made it through eating mostly cold food, but i would have been much happier to have hot oatmeal in the morning instead of cold. also, investing in a stove (or making a pop can stove) is worth it because you can eat more grains which are cheap and healthy. i was lucky enough to have food stamps at the time and i got about 200/month. even with that,when you're eating 5000 calories a day, you have to try and get the most calories per dollar. i used to soak rolled oats and chia seeds (lots of good fats, fiber, antioxidants in those) then i'd add some dried fruit and nuts and eat that first thing in the morning. i sustained myself mostly with peanut butter, dried dates and raisins, nuts, seeds, corn tortillas, canned sardines (the cheap ones can be really gross, though), fritos (a lot of calories per small bag), avocados (don't last long in your panniers) and bananas. you want to make sure you're not just eating empty calories, and try to eat green veggies so you're digestion doesn't get all outta wack.
if you're interested in reading more about nutrition, this is a good article about what ratios of protein, carbohydrates and fats you should be eating, and WHEN to eat what:
http://www.bicycletouringtales.com/nutrition info.html
stores with a big bulk section are wonderful - sometimes they have dehydrated hummus or soup mixes that are lightweight - and bulk is almost always cheaper than buying the prepackaged stuff. also, you can take as little or as much as you want, and if you're going through a lot of cities, just get as much as you need to sustain you to the next town and refill. i tended to carry more than i needed because i was afraid of going hungry, but you'll learn from experience how much food you need.