One easy thing that can save your diet is having your food grilled instead of fried. It can get boring eating all those grilled chicken sandwiches, but the difference in calories is worth it to me. A grilled chicken sandwich is common when we stop somewhere on the road, and if I get lucky there is a grilled catch of the day to choose from as well.
Here is a good example from everyday fast food to demonstrate the caloric difference between grilled and fried chicken. A fried Chick-fil-A sandwich has 430 calories and 17 grams of fat while a chargrilled chicken sandwich at the same restaurant only has 290 calories and 4 grams of fat. Knowledge is power when it comes to your diet, and counting calories is a great way to get knowledge.
In my travels sometimes I splurge on food that I would not have eaten on a normal day, but I try to only splurge on 1 item. For example if I decided to splurge on the fried sandwich I would get a salad instead of french fries, but if I got the grilled sandwich I might just treat myself to those french fries. I also try to make sure I am active when I travel as well to help counteract some of those little splurges.