OP here. Thanks for the ideas. I was thinking of lasagna or baked (not breaded or fried) eggplant parm, I just never make lasagna very often so I wasn't sure if I baked it and then traveled with it in the cooler (4 hours) and then reheated it if it would still taste good. Sounds like I should just go for it.
Doing it in advance will only make it better. Gives the flavors a chance to meld. I always think lasagna is way better the day after than when it's just out of the oven.
Just make sure that you've thoroughly cooled it before you travel. If you make it and then put it right in the cooler to leave, it will be a bacteria fest during your 4 hour trip. Instead, make it the day before and refrigerate it overnight. With a thorough reheat when you get there (oven, not microwave), it will be awesome.