What could i eat at these common reasturants that is Kosher?

Ok well most likely soon I will be converting to Messianic Judaism which means kosher food, my sister is on 2 select basket ball teams which means in between games we have to go get food so if I do it I need to know whats safe. these are some of the ones we would usually go to- McDonald's Chick fil a, chillis, sonic, subway, dairy queen, jack in the box, taco casa, red lobster... ECt just common things... so things i could get? that would be ok i cant bring my food what ever it is cant be taken in the gym or left in the car so yeah