Keeping Food Hot & Delicious

Depending on what it is I am transporting I use different methods, and I use the same methods for both hot and cold transport.

The easiest is the towels in a box; lay four towels down in a shallow box, hanging the other ends of the towels out each side of the box, then put your dish or bread or pot or whatever in the box and fold each of the four towels over the food. If you have hot food, lay some more insulation material over the top, as heat rises. If you have cold food, put the box on the seat, not the floor, as the floor will conduct heat from your vehicle up into your food.

I always have a sleeping bag in my rig and I will sometimes wrap food well with towels and then open the sleeping bag and shove the food into it, wrapping the rest of the sleeping bag over the top if hot food and under the bottom if cold. This has worked a lot for frozen foods when I go bulk shopping in the city, holding food frozen food for 4 hours and more.

All the cast iron pans I've got came with instructions that read along the lines of "suitable for serving, but not storage of food".

I'm not sure what would suffer most though, your pan, or the food, or both, depending on length of time. My guess is that the length of time you actually can store food in a cast iron pan/pot safely somewhat depends on the ingredients used. For example, a tomato sauce would be less good to store in a cast iron pan than fried potatoes.

Regarding the temperature, I'd say it depends on how well insulated your "bag" is. Cast iron distributes temperature very nicely, but that doesn't necessarily mean it will cool less quickly than another type of pan (of same size/thickness) when taken off the heat.

Regarding keeping food warm, I did see insulated pots similar to a thermos flask you'd use for hot coffee or tea, which are made to store food. They have a big enough opening to be filled, and to be eaten from.