One word of caution when going to East Fork Rock. Bring plenty, and I do mean plenty of water. Also, watch yourself around those blind corners and be conscience that most if not all the mapped trails are two way trails. You can go fast, just be aware that you will encounter incoming quads and dirtbikers. Show proper trail ediquate as well, as in holding up how many fingers as there are people behind you.
I'm not trying to patronize you by any means. I went to East Fork Rock last Memorial day weekend and severed my top triple clamp in half because of a guy who came flying around a blind corner and hit me head on, dirtbike to dirtbike. He had an idiot up ahead he was riding with that didn't give me any sign whatsoever of how many riders were behind him. Both were going way too fast for these trails and were very inconsiderate of the "tread lightly" motto that I abide by. I had a seven mile ride back to camp in the rain.
Besides that, its one of the greatest places I've ever been to. If there is one trail you are going to go up on, the East Butte Lookout trail is by far the best. Actaully, go visit all of the lookouts if you have the time, they are simply amazing with the view they give you, take lots of pictures.