I've cooked...really cooked in the truck for years! Had every kinda cooler, fridge you can imagine and the thing thats workin' for me best now, is that SMALL cooler for leftover Chesters, Arbys, etc. I have a microwave and the lunch-box heater. I do alota Nissin/Ramen meals (nuked) with Chesters, spam, whatever added in. Cup-a-soups are a big deal with a walmart double cheeseburger (landshire). Most of what I use is DRY or CANNED so no need for refrideration. Spice grinders do wonders for CBRD. A can of chili heated in the heater poured on a w/mart burger=reneck "chili-size". The heater is the best thing if ya can't add an inverter and M/W.
I agree, I started out at May Trucking, had a 2000 watt inverter so I had a fridge and a microwave. At the pumpkin now and the biggest inverter we can have is 300 watts. No fridge or microwave now. But I got 7 12 volt outlets in my Cascadia. So the cooler and and lunch box heater works pretty good. Do miss my 2000 watt inverter though.