I have cooked fish this way several times and it actually works quite well, never made a full meal, but it cooked the fish and provided a hot meal. The old in line 6 engines were the best as they had a nice easy to access manifold.
I don't tend to worry about a hot meal after a long day of traveling, whatever my DW puts in front of me I eat, hot, cold or somewhere in between. If we can refuel and eat out later in the day we try to do that so we can relax when we stop get a decent start in the morning.