The other day I forgot my lunch and ended up in a convenience store to buy lunch. Japanese convenience stores often have hard boiled eggs. They are in the "deli" section with salads. They are sold as two or one egg (vs. a pack of 6 or so which would be raw). I also got a banana and a cucumber! I had some salt in my car so it worked out fine. Sesame oil makes a great tasting salad dressing to put on veggies. I haven't had a problem with take out sushi packs but I avoid anything with seaweed in it or anything with a sauce.
Also Soyjoy bars are gluten free: