traveling and staying on plan, especially phase 1 is difficult without planning. i always bring a cooler and stock it with phase 1 friendly snacks. hummus and cut veggies, celery and pb or laughing cow, string cheese, deli meat wrapped around pickles, etc.
You can always order a sandwich or wrap and just eat the filling. My family knows that road trips mean special stops to places like Sonic. We hardly ever eat there so it is a treat. I order a grilled chicken wrap, no sauce or cheese, extra lettuce and tomato and then use the wrap as a plate. You could grab a small side salad as a side and top it with the filling from your wrap.
It just takes a bit of planning ahead and thinking outside the box.