I brought my 2yo boy to this event two years ago. I have a photo of him in Tony Scarlota's capsal boat somewhere (thanks again JBG). He had a great time. I don't remember a sand box or playground, but he just stayed with me the whole time (he's good that way).
You should be fine taking the lil'girl.
Make sure you root for my buddy in the 006 Hondo T-Deck - Robert Ojeda (aka 77Charger)!!!
RTJas