I did credit card touring in France with two mid-sized rear panniers, a small daypack bungee-corded to the rear rack, an under-the-seat wedge pack for my tools, a plastic map case velcroed to the handlebars, and a fanny pack.
There was more than enough space for my stuff plus the food that I bought daily. But I carried no camping equipment: no tent, no sleeping bag, no stove, no fuel.