Great cross country riding
The overview is a little misleading. None of the trails start from the campground. You have to exit the campground and follow the paved road west to the end and go around the yellow gate. The river run trail is a little hard to find but starts right after the gate on the right. The PDF for this ride along with an app like Avenza is a must-have for way finding. There are no signs anywhere, but the trails are well defined by all the horse riding out there. The horses also tear up the trails a fair amount so some climbs/descents are very loose sand and dirt. I would imagine these trails are a mud pit when it rains.
I rode the magenta loop in the PDF backwards and the lower part of the green loop (river ridge trail). Excellent riding with great views and a variety of terrain from meadows to forest to slickrock. The "river run" trail is very beginner friendly. The only obstacles on it are the two river crossings and numerous horse droppings. Other trails have steep climbs and some roots and rocks, but are generally non-technical. Mid-week I only saw 2 horse riders and 2 cows over the course of several hours of riding, so it's very quiet out there.