h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

May I humbly suggest a few very important items to be taken along whilst camping in the wild:

Firstly, an easily referenced guide to the food chain with your position on it clearly indicated. This is important for two reasons. You may need assistance in finding something edible should you become lost.

Secondly, upon encountering any native wildlife, one needs to quickly establish whether or not you are part of its customary diet. In these cases what you do and how quickly you do it will have a great impact on whether or not you become an entree.

When camping in the United States extra measures are advised. It is wise to carry a pocket copy of the FBI's most wanted list. American campers have had more than a few unhappy encounters with those they have met in the wild when it turns out that their goals for being there is not to observe the marvels of nature.

and only drink water from clean fast-flowing sources, after checking upstream for dead animals.

Iodine tablets or other water purification systems may be necessary as well as boiling, depending on where you're travelling. I speak as someone who goes walking in the English Lake District and Scotland - don't know what you'd do in an area of swamp.