I raced the Gravel Grovel yesterday. It's a 60-mile gravel and off-road race in southern Indiana.
Due to a wrong turn (by nearly the whole group) right at the beginning, we had an extra four miles and two climbs.
Most riders seemed to be riding either 'cross bikes or mountain bikes, but I don't have either of those. I rode my LHT. I removed the fenders and put 700x47 tires on it. It behaved wonderfully on the gravel. It wasn't the ideal bike for the off-road section though.
It was painful, but fun. My goal was to finish within 6h:30m. I finished in 6h:13m, which makes me quite happy., That way I didn't miss the award ceremony or the food.
Here's a video someone took of last years event. It looks very similar to my experience.