I first used a Dutch oven when I was working for Backroads in the mid 1990's. On camping trips (Yes, I did mostly hotel trips, but I did do 7 camping trips!) we would stack up to 4 Dutch ovens and serve breads, coffee cakes, lasagna and many other things I never imagined could be prepared on a camping trip. Years after leaving Backroads my wife and I purchased our own for personal use. Please note that we use Dutch ovens for camping using charcoal briquets and that any cooking times mentioned are camping specific.
Cast Iron or Aluminum?
Although Backroads used aluminum Dutch ovens, our first purchase for personal use was a Lodge cast iron oven. It was very heavy and we followed the steps to pre-season them. After using them once, I dried them and put them away in the garage. A year later, they had a few spots of rust on them and I decided I would buy an aluminum one. After that we bought 2 more aluminum ones and I gave the cast iron ones away. Aluminum may not have the character or non-stick attributes of a well seasoned cast iron model, but they are less fragile, much lighter, require no special maintenance or setup and rust is a non-issue. There are die-hard cast iron Dutch oven fans that will passionately argue in favor of cast iron, but I’m happy with the aluminum ones. Buy whichever you feel comfortable with—either kind will last a lifetime with proper care. The good news is that you don’t really have to fuss with the recipes for either kind of Dutch oven.
What other equipment do I need?
Of course you will need charcoal briquettes. I don’t have any experience with fancy, organic briquettes—we just use Kingsford and have not had any issues. We use a heavy gauge aluminum jelly roll pan as a base for our Dutch oven. It fits on just about any campsite barbeque grill or you can prop it above the forest floor with rocks or wood. Generally, depending on where you are, it is not cool to place briquettes directly on the ground. Note that the jelly roll pan will get enough abuse with the coals and Dutch oven that you won't want to bake cookies with it. I prefer heavy aluminum jelly roll pans since they are lightweight and mild warping (if any) is not an issue for this application.
You will also want a charcoal chimney to get the coals going and to keep a steady supply of replacement coals ready. If you are also traveling with a stove, you can place the chimney right on the burner and skip the newspaper. Once the coals are good and hot, you will want to have some extra long tongs to arrange the coals above and below the oven(s). Leave about 8 - 10 coals in the chimney and replenish them with a couple fresh coals every 5 minutes or so as you add more coals to the ovens. A good dutch oven lid lifter (one that can be used to also lift the entire oven) is also very handy for peeking and moving ovens when cooking is done or you are replenishing coals in a stacked oven setup. Finally, an oven mitt is handy for removing/replacing the lids when serving firsts and/or seconds. The Dutch oven cases aren't a must have, but they are nice for keeping the lids from rolling away during travel. We store most of the briquettes we use inside the Dutch ovens inside a brown paper bag. Anything to save space.
Cooking in a Dutch oven
I tell people that Dutch oven cooking is like cooking in slow motion. If a dish takes 20 minutes to bake at home, expect it to take 30 - 50 minutes. At home, when something is almost browned, you check it again in a minute. With the Dutch oven, no problem—check it in 3-5 minutes (have another beer). It’s difficult—but not impossible—to burn things in a Dutch oven. You really have to be into that beer to let things get burned. The two main challenges with Dutch oven cooking are timing and browning. Most recipes generally require about 7 - 9 coals beneath and about a 12 - 15 on the lid for a 12 inch diameter oven (if they even specify this detail). Varying the amount and distribution of coals (along with stacking ovens) can greatly affect browning and cooking time. Another challenge is making too much food if you are only 3 adults and 2 kids most of the time, though you can use foil to make a bumper/dam in the oven to maintain the right depth of something like a cake. As you get experience cooking dishes, you quickly realize that nearly everything you can bake at home you can pretty much make in a dutch oven. Recipe selection comes down to preparation time and difficulty (e.g. is there a lot of stove activity or proofing required beforehand) and availablity of ingredients. It's a good idea to practice new recipes at home before showing them off on a camping trip.
Timing: How long will it take?
As mentioned, cooking times can sometimes be almost double in a Dutch oven. Wind and altitude can be a variable that affects cooking times. You can reduce cooking time by really piling on the coals, but you run the risk of burning if you overdo it. Wind can also increase cooking time. If it is really windy, consider some type of makeshift windscreen to protect the ovens from the wind. Timing also comes into play when you are not making a single dish meal—which is usually most of the time for us. Larger, denser dishes take longer to cook than simple breads and cakes, so you start those first. You also have the challenge of timing with other non Dutch oven dishes you are preparing. The good news is that you can remove the Dutch oven from coals and they will keep warm for quite some time with the lid on (even the aluminum ones retain heat well).
Browning (i.e. not burning the bottom in an effort to brown the top)
I think this is the bigger challenge since timing can be remedied by letting some things sit. Getting your breads and cakes to be golden brown on top and not dark brown on the bottom takes a little skill and practice, but the general tip is to not place more than 6 coals or so on the bottom and place more coals than normal (15 - 20) on the top. This means that if you are stacking ovens, you can’t place that bread on top of something with a lot of coals. And, what is above the bread, if anything, needs to be tolerant of a lot of heat below (stews would be a good example). You can always just not stack, too. Also keep in mind that too many coals on top might brown the top too quickly while the center/bottom are not fully cooked yet. It’s best to not rush things so avoid temptations to really go nuts with the coals and just allow for more time. Go ahead, open another beer.
Not just for cooking
We sometimes use one or more dutch ovens as a food warmer for pancakes, bacon, or sausage by placing one over a pot of simmering water. The simmering water doesn't go to waste as it is great for doing the dishes.You can also place 3 - 4 coals on the lid and another 3 coals below the oven. We like to serve meals family style, and having all of the dishes still hot is a must for happy campers.
We line our dutch ovens with aluminum foil and usually there are no leaks. Even when there are, soap and water are all that are required. The foil also makes it easy to lift out cakes for serving or for immediately halting cooking for breads that are done.