Vegetables can be preserved for a long time without refrigeration (depending on temperature). You’ll know when they get bad. As far as a leaving meat unrefigerated…I don’t recommend it because it can go bad within an hour or two if being left out (depending on temperature). Some meats last better than others, but a whole chicken breast for instance would be a little iffy.
You can store your foods in tupperware containers, etc…and transport in a lunch bag.