If you happen to have a broken washing machine, the drum makes an excellent barbecue. Turn it with the hole facing upwards and then chuck some hot coals into the bottom. You can put a griddle on top and use it that way, or a wok is just the right size to sit in the hole and cook up a stir fry or pan fry some fish. In Cornwall we had fresh mackerel cooked like that. Basic Equipment A pan - the size will depend on how many people you want to cook for, or on what you happen to have.
Potatoes are heavy but they're worth it.
Bread goes off really quickly, but you can just eat it, and you'll probably be able to buy it on larger sites. Try long-life bread if you don't mind the vinegary taste. Fresh vegetables and fresh meat always taste the best and are the most nutritious. They will last for a weekend, but you'll need to store them carefully to prevent contamination by insects and bacteria. Tupperware boxes are ideal - knotted plastic bags will do for vegetables and cooked meat.