For me, it depends on the weather. If the weather is hot, we like to go with cold sandwitches. We prepare them after breakfast, before we head out. If it's colder, we like a hot meals. We prep lunch items, wrapped in aluminum foil. Before lunch time, we pull over for a short stop, and load the engine with the prepared items. We let the engine heat up lunch, as we drive. When we are ready, we find a nice spot to stop, and have a hot lunch.