In reply to Roobag:
i doubt this race has technical sections. I haven't run it but you are right to investigate if off road means all gravel and packed dirt or if it's soft mud, sand. If it's all fairly hard, and the shoes feel hard now they won't feel any better after 8 or 9 miles and very sore feet will mess up your stride and biomechanics leaving you very slow and very sore.
Edit. There's a bit of beach, a bit of road and a bunch of concrete wall that will feel very hard. Tricky
Post edited at 10:14