Anyone have experience/tips/ideas on planning a biathlon??

So our school year is about to end and my school activity group has decided to take a leap of faith. We're looking at planning a biathlon type event for our kids and their parents to promote awareness about sports for children with special needs. The participants will mostly be children with autism who are just starting out with sports so we're looking at a really simple event that will be running (instead of skiing) and throwing at a target (instead of shooting). I have SOMETHING of an idea of how to start it off but if anyone has any experience in planning a biathlon or multisport event (for people with special needs or for typical athletes, adults, children, whoever), I'd really love to hear from you. Mostly ideas on organisation, scoring, managing the crowd. And worst-case scenario type of stuff happening so we can anticipate anything that might go wrong (Murphy's law always happens). Basically, if you have input, I'd love to hear it so it can be fielded at planning sessions. In advance, a huge thank you!! :D

Bump, because I'm looking into planning a 5k/1-mile Fun Run for our end-of-the-school year celebration, too.

Roxy