I actually just went to one a few months ago in NJ. It was all together a good time, you learn a little bit about what your truck can do.
They had ours broken into 3 sections, an arena type deal where they had various obstacles including inclines, descents, mud, a little water, rocks. Then they had a track which was gravel which they let you compete with the other LRs for time, donuts and a cone ralley. The last part of the event was a trail, took maybe an hour total time to get through it (some drivers had more troubles then others). They have spotters at all the obstacles throughout the day and they will tell you everything as to what gear to be in, which way to go, and how fast to go.
It is tame compared to an actual trail experience, but if you are either a very beginner or even intermediate i'd go for it. It's a day out on the trail and a free lunch!
