Has anyone done this event? It has a 1K in the sand, then a 30K bike ride, then a 5K run on pavement. I'm a little worried about not keeping up with folks if the majority of participants are super-fit Marines. I'm mostly concerned about running, especially in sand. (I have no idea how I'd train for that portion on any sort of regular basis, since I'm an hour from the beach.) Has anyone done this event, and if so, is there a wide array of participant levels, or is it mostly highly competitive, Olympic level athletes and kick-*** military folks?