For a three day tour I recommend having all your food with you and not stopping to buy groceries. To stop and buy groceries would be a waste of time in your case since it does take time to find the things you want. Aside I think you should have a food supply buffer if you don't find a place to purchase food. My staple menu items are:

Breakfast:
- The quick & no-cook option: Beagles, tortillas, or something else bread like with Nutella.
- The normal everyday option: Oats & granola mix with Nido whole milk powder (much better than your regular milk powder) and hot chocolate powder.

Lunch:
- Tortillas & tuna (in a pouch).

Dinner:
- Flavored rice pack (i.e. broccoli cheddar cheese) & can of goulash.

BTW, I found that I don't care for a lot of sweet snacks. You might experience the same, so pack some salty things as well.

Tons of great ideas and I'm getting alot of planning time in. Unfortunately the expenses are running a bit high for my part time/college student paycheck haha. Gonna continue planning and go onthis trip after my summer session classes so I will have all of my gear sorted and tested out as well plenty of spending money.

Definately not giving up on this plan tho, simply putting it off a month until it will be 95 out and packed with tourists lol

Thanks for all the input, definitely helping my packing list