About to move to Colorado from Australia (Denver)

Hi, I'm needing some advice. My husband and I and our family (twin 8yr olds and a 6yrold) are about to leave Australia into the great unknown of Colorado for work. He's a nurse and I currently homeschool. We're coming on an E3 visa, and are wanting to know about are we eligible for the Public School System? Reason being, I've been looking into the k12 online academy public school option. Does anyone know about this? It's totally free with all curriculum materials provided, yet you school your child at home. I've been contacting all the possible people I can and getting no answers. Even Colorado Dept of Ed! Any guidance would be much appreciated.