We use these a LOT. We've got two cast iron Lodge camp ovens (same size - 12", IIRC; one is "deep"). I'm more likely to use a campfire (coals) than manufactured briquets with those. Also have a 12" GSI hard anodized AL camp oven that I really like BUT I'm chicken to use that as an oven (say, for biscuits) - too expensive to "oops!", though I suspect it would take some serious inattention to actually melt one. It cooks just as well as the CI and clean up is trivial.

Also use two conventional cast iron (also Lodge) Dutch Ovens - no legs - in the home ovens. They excel for roasting things.

Google "straw box cooker". One of these days... I've used one (not mine) and that IS the crockpot of yore. What I have done many times (where appropriate) is dig a hole at basecamp and start a wood fire beside it while fixing breakfast - bringing my DO evening meal to boil over the fire. Before heading out, I dump most of the coals in the hole, lower the DO in, the rest of the coals, and then all the spoil (dirt) loosely and mounded. When we return in the evening, supper is ready.

I'm going to splurge on one of those tiny 10" GSI hard anodized DOs soon - I think I'll get a lot of use out of it on 2 - 3 day outings.