Overnight oats, perhaps with some chia seeds mixed in at the last minute if you find they're too sloppy. Between mixing half a tsp in at home, & eating them on the train, they can thicken up a heck of a lot. And good protein source. I like HFW's recipe for Bircher muesli as well. Most dried fruit is good in overnight oats but I personally dislike the texture of rehydrated dried banana. A lot of nuts & seeds work too. Can batch maker this - do a couple of days worth at a time. Lots of ideas on Pinterest etc.
Dinner, any combination carbs, protein, veg / salad. Doesn't need to be heavy. Dressing in a separate container - test it out first to make sure it won't leak. Freeze a carton of juice to use as an ice block, or just use an ice block. Fruit. For nice salad ideas I like:
Tabbouleh with any protein you fancy, green leaves.
Hummus, falafel, grated carrots, green leaves, tomatoes & olives.
Greek salad & some diced cold roast beef.
Sandwich - make it a nice one though. On your favourite bread.
Tuna, hummus, grated carrot, alfalfa sprouts & a few cumin seeds.
Cold roast chicken, lettuce, mayonnaise.
Cream cheese with smoked salmon & baby salad leaves or cucumber, scoop out the cucumber seeds before slicing to stop it going soggy.
Cheese, ham, tomato or pickle.