Grabens Loop is located in the upper portion of Overend Mountain Park (aka Test Track). It can be accessed from Hidden Valley, Star Wars or Ned's Hill. It's a fun rolling loop with short (sometimes steep) climbs and descents. There are many trails in this area, so navigating may be a bit difficult. All main intersections are marked with trail maps, so otherwise generally follow the most well used trail and use the MTB Project MTB Project mobile app.