Bake things kids can pick up - like brownies- or the cones with cupcakes in them as Sally suggested. Also carrott cake or banana bread are easy to make and easy to transport.
Also- along the cone line- am reminded of what my mom used to make at Xmas- take ice cream cones (sugar cones9 turn over so flat side is down. Ice entire cone with colored icing (regular decorators icing). Before it hardens - use candies - popcorn - whatever to decorate. Little kids love these.
Chocolate chip cookies - but made into bars are also really easy and easy to transport and sell as one item or separately.
GOOD LUCK!