The place I go to specialise in sparkly things for dance costumes, so they prob know of a method that is safe for synthetic fabrics. I will be going there in the new year, wil let you know what i find out.
They have horseriding right next door to the resort and you will only be at most about 1/2 hr drive from the theme parks. You can pre purchase super passes that get you into the parks cheaper and they used to do a deal where you could go back to the same park the next day for 5 bucks, which is great if the kids really loved something.
Also heaps of beautiful nature walks an national and state forrests around. Corrumbin Sanctuary is great if your kids are into critters.....