Tie it down under the hood
This is where it gets tricky, because where you put your food depends on how hot it needs to get to cook properly, but also on how long you plan on driving. If you're only going on a 30-minute jaunt, you should find a spot much closer to the engine than I did here, because it'll take the engine up to 20 minutes to get nice and hot. The best course of action is to feel around (carefully!!!) under your hood after you get home from work someday. See how hot different sections get -- the exhaust manifold is a sweet spot for engine cooking.
Wedge your food so it won't get dislodged during your drive. Hot dogs, for example, won't leak all over the place if you put them sideways, but for eggs? I took no chances, because I could already imagine the phone call with Toyota's reps. "No no, the truck was great. Yeah. That's egg. I'm a klutz."