Flying Blind

I'm out in California for work.  No scale.  Dinner out at a restaurant every night.  I have no diet measurement for my meals.  I'm making sensible choices, but I have no idea what a plate of chicken fajitas is in terms of calories.  I figure it can't be that bad.  No cheese, grilled white meat & vegetables, some rice, and a side of beans (not refried beans).  It seemed pretty healthy, but I don't know if I should call it 1500 calories (like fajitas at Applebee's) or 800 calories (like fajitas at Chevy's).  I'm just flying blind.