The Bacon Ranch with grilled chicken salad from McDonalds is pretty good, and so is their Fruit N Walnut salad, and their Yogurt Parfaits-all are healthier choices than the regular burgers/fries fare. Order a water, or a diet soda.
At Taco Bell, a spicy chicken soft taco isn't bad calorie wise at all-and it is also made with lettuce and salsa, instead of fatty/calorie laden cheese and sour cream. The Zesty Chicken Bowl isn't too bad on calories and fat, either-since there is no fried shell...and it is chicken/beans/rice as the bulk of it, rather than beef/cheese.
You got some good suggestions for Wendy's-my favorites are the salads, and the chili. A small chili is under 300 cals, and a large chili is under 400 I believe-check the websites for the actual nutrition info on these items.
At the larger Dairy Queens, where they sell food as well as ice cream, they have sugar free/fat free bars that are around 60 calories each...and salads, etc. as well.
Good luck!
Aphil