In reply to trish1968:
Did it a few years ago. My nav was awful but got lucky and ran with some people who knew the course, recce would probably be a good idea.
Are you running or walking? If the former, be aware that there are almost too many checkpoints, and you can lose hours eating cake if you're not careful. Try and in and out in a few minutes or less (master chewing on the go). The last stretch is the least interesting, from what I remember, so be prepared for a bit of a slog at the end to get it finished.
It's a really good event anyway, have fun.