One alternative to the pachamancha pit is the “haybox cooker”. My experience involves only foods cooked with lots of liquid, but the idea is to get the food to a rolling boil, then pack it away in a well-insulated environment for six hours or so. Traditionally, people used a box filled with straw, but modern alternatives exist, typically in the form of a simple metal pot and an insulated larger pot with a tight-fitting lid. Amazon should turn up several examples under the search term “thermal cooker”.
– EQR