Hummus with pita bread and/or veggies. Wholegrain pancakes are good at room temp leftover, smear with PB for protein. Ferro salad with veggies, again, good at room temp. Leftover homemade pizza.

Have you looked into a Yeti or similar thermos? They work much better than traditional thermoses, but they are expensive.

I haven't looked at Yeti. He thinks the thermos is fine, stuff isn't piping hot but it's good enough. Thankfully, he's not picky. :)

I like the idea of the hummus or pancakes. With a salad, that would take the place of a sandwich. I have just started learning about canning jar salads, I think I'll definitely be pursuing some of those.

He's agreed that he might be able to install a microwave in his trailer, with a little re-engineering.

There are all sorts of lunch packs/bags to which you can add reuseable freezer packs to keep things cool. I would check into something like that for summer.

That Crock Pot is an interesting idea. It might work on days that he stays in one place. Some days he's at 5 different jobs before lunch! But he knows what his day will be ahead of time, so we could plan a little. Any idea how long it takes, say, to heat up a can of soup? He has power in his trailer.

Yep, the cooler thing is much easier than the warming thing!!

I was going to suggest anything you can make in a crock pot. For the thermos, did you try the trick of adding boiling water and leaving it for 5 min. or so before dumping, drying, and adding the heated food? That seems to help.

Protein shakes? Vegetable sticks, peanut butter on celery, crackers and cheese, dinner leftovers, hard boiled eggs, egg cups (eggs, veggies, cheese baked in muffin tin). Almonds, avocado, and other healthy fat. I would focus on dinner leftovers, if it were me, along with batches of things you could make ahead of time.

Yep, we pre-warm the thermos.

The veggies, eggs, nuts could work nice on days he's driving a lot. He could nibble as he goes. Would the egg cups be good at room temp?

MTA: I guess they would. They're basically quiche in cups, right? That's OK eaten cold.

Yep, egg cups are good at room temperature. In fact, if I can’t eat them hot, i prefer room temp to cold. There are tons of different recipes for them too. With also many people eating low carb, it’s a popular thing to eat.

My daughter puts a can of soup in around 9 a.m. and says it's piping hot at noon. I think you would need to experiment. There's no reason why the crock pot couldn't stay connected to DC current while he is driving from place to place as long as it didn't run down his battery and was situated so that it didn't spill.

Then, there's always this:

Book Link

That's it!! Manifold cooking, what's not to love?? And bonus, it would take me out of the equation. :p

I have a friend who has something like this that she uses in her car when traveling and in the house when she brings food for a weekend gathering. warmer/cooler

Well that's nifty. He could store the entire week's lunches. :p I'll have to poke around and see if they make a smaller one.

for ski trips, I keep certain Items portioned in the freezer. On the day of the trip I take the servings I need, reheat, double wrap and put in a cooler with hot stones. I make empanadas, stromboli, frittata, strata, tamale pie, enchilada casserole. Hearty foods for cold days on the mountain.

I often take homemade baked meatballs for lunch. You can use any meatball recipe, just form balls, then roll in breadcrumbs, drizzle or spray with a little olive oil & bake @ 350F for 25-30 minutes, then simmer in sauce 20 minutes, if desired, though I prefer them w/o the sauce for lunch on the go.