Hi Mike,
I did 1500 miles in 24 days last summer (Pennsylvania to Florida). $25. a day will be tight. You must eat on a long trip. Carbs are easy. I got most of my carbs from stuff I could find at small grocery stores and gas stations - pretzels, hot dog buns (yes, hot dog buns!), bananas, raisins, and baked potatoes when I stopped at a restaurant. More importantly, I drank loads of Gatorade (I did my trip in 90 - 105 degree heat). Not once did I bonk. If you don't know what bonking is, research it. IT IS CRUCIAL. On a long ride you must constantly feed yourself every 10-20 minutes with small snacks) or you will hit a wall and run out of gas. My Gatorade and water bill averaged 8-10 dollars a day. If you will be traveling in cooler weather, obviously plan on less. Beware of filling your water bottle at sinks in bathrooms to save money. Sometimes you get well water that your body may not be used to. Avoiding the shits is critical. Protein is tougher to come by. I drank a lot of milk and ate Greek yogurt when I could find it, but never passed a steak house at dinner time. If your budget does not allow for (reataurant) steak, (self cooked) eggs are a great source of protein. Cheap and fast. However, you wind up throwing away what you cannot eat because you obviously cannot carry them. But even if you buy the dozen and eat four, that with some bread and a banana makes for a three dollar meal. I am not a picky eater so basic carbs and protein were what I looked for. Not fancy meals. Like I said, I did my trip in a heatwave and in the northern section of my trip, I had lots of long hills. I had 30 pounds of gear in two panniers and averaged 73 miles a day. I started my trip at 219 pounds and rolled into St Augustine at 215 pounds, so I didn't lose much weight. I only got stronger as the weeks rolled on so I figure my diet plan worked. If you will be passing and Waffle House Restaurants - they were my favorite. Three eggs, two chicken breasts, toast, and milk always powered up my day in the morning - for about ten bucks. By the way, I averaged about 40 dollars a day for food. Tell me a little about your trip. Where are you going and when and where are you starting from?
Eric