Having never sucked on a crawfish head, I have no idea what you're going through in that regard. But, you are the Queen of Resistance to Temptation for driving past those smells. I have heard from people who have been to NO that the smells drive you crazy and you can always get something to eat there. The smell of fried chicken gets to me but it DOES get easier!
Now I'll tell you funny story about a Mom and Pop chicken place that Mr. D took me to before we were married. It was over on the west side of the state, can't remember where exactly but Mr. D went there often because his work took him there. I went along one day just for fun. We had our dogs along, he had a sheltie and I had at least one of my shelties and my collie in the back of his truck with the cap on it so they had their own travel area. The dogs learned pretty quick that whenever we went somewhere, it was for FOOD and they always got their share when we came out. Mr. D would open the hatch on the back and give them pieces of whatever it was we had, or "foo" ice cream at them. Which is a whole 'nuther story but also quite funny. But, I digress. So, we went into this greasy fried chicken place, famous with Mr. D because of the deep fried chicken gizzards you can get there. Why anyone would want to eat a chicken gizzard is beyond me, never liked them, but anyway. These particular gizzards were wonderful, he said, and they had gravy on them. So, while we were in the place eating lunch, the dogs were in the truck all that time, smelling the smell of the fried chicken, they were right outside the door because it was a small parking lot. We came out, Mr. D holding his paper plate, and I opened the hatch. All the dogs were right there, and they were READY. The collie was absolutely quivering with anticipation and barking, all the while drooling all over the tailgate of the truck. It was just dripping down from his beak, all over the bumper. There were also puddles of drool all over the back of the truck!
Which I had to mop up, of course.
But, seriously, you did SUCH a good thing passing up all that stuff. You hang in there, it gets easier and easier. There will always be temptations but you can deal with it.
Can you keep a cooler in your vehicle with an ice pak and some apples or carrots or something to eat on the way home?