Unless your going to depend on a charcoal grill or traditional campfire, both of which have major issues and weaknesses, you going to want to get yourself a portable stove of some sort.

There are a lot of makes, models, options and general ins and outs at every turn. Researching the available options isn't easy and, often on any single page, the opinions will often contradict themselves.

To help you along:
http://zenstoves.net/StoveChoices.htm

Look around the site and you will find a fairly detailed examination of stove types, fuels, plans for stoves you can make, many out of found materials, and links to related sites.

Personally I have a charcoal grill for recreational home use outdoors, a single burner propane model for inside use during emergencies at home, a Svea 123 white gas unit for hiking and camping, and a fan blown wood burner for after disaster and long term use. I figure seeing as that there are plenty of woods around there will always be wood.

When considering your stove choices remember that boiling water is a good way of treating water that only requires a pot and fire. It vastly increases you fuel use but can eliminate the need for chemicals and most filters. The possible need for unlimited fuel pointed me toward wood as a long term fuel source.