How to walk home when it's hot outside

Actually, it's not too bad. I won't complain about 83 °F and 22% humidity. I know it can get a lot worse here, but I'm enjoying the low humidity while we have it.

Geek Girl has art camp at the recreation center this week, every afternoon from 1 to 4 pm. I drive us there because if we walked we might not ever get there and I go run errands while she's at class. However, since the class is really only 15 minutes walk away (when I'm by myself), I walk to pick her up and we walk home together (and it takes 30+ minutes). How do I keep her moving and happy? I give her a spray bottle filled with water. That way she has a fun way to drink water and cool herself off and water the plants on the way home.