Portable Fire Pit
Cooking will be dependent upon the venue and fire rules. Some will only allow for a contained fire and no pit. If possible, try to find a back yard portable pit such is shown in the photo. What should not be used is a large “Clayton Style” stove. This would not be correct for a military camp. A small brazier would suffice for demonstrating how water might have been boiled. Assuming you can get past the safety concerns on the fire, consider either stew in a cannonball kettle or a roast on a spit. Both very period correct. Always have a period correct pail of water next to your fire.