I rarely transport prepared cooked food. If I go to a restaurant I eat there. There is one thing I do transport that is cooked. It is a bucket of three types of appetizers. I have the place wrap it in a plastic sheet and put it into my back pack. It always arrives squished but it doesn't matter. The individual chicken strips, popcorn chicken, and popcorn shrimp, are unaffected.
Last year I went to a pot luck lunch for work and brought two glass casserole dishes full of sausages. I carefully placed them at the bottom of my back pack and made sure I didn't swing it in any way that would spill the contents.