Just opened in 2013, the Sled Springs OHV area has more than a few advantages for mountain bike riding. One is that it is beginner friendly and great for family riding because of its mellow climbing and open tracks. Since it is near the Chico Trail, there are plenty of options for riding for all levels. It also includes some historical value as you are riding right across and around the Sled Springs stagecoach historical site.
Most of the system seems to be on forest roads and hasn't yet evolved into a narrower doubletrack. Some of the route shown here has been newly developed trail dedicated for ATV, so it has a more remote feel to it. A trail map should be available at the trailhead and the trails are mostly marked with a numbering system. Each marker at least had an ATV symbol if it doesn't have a number, so the routes are pretty easy to follow. This route is just a small part of the entire system, but it is closest to the highway and takes off from the main staging area.
There is no sign from the highway for the park. Look for it north of the historical marker on Hwy 3 if traveling north from Enterprise, Oregon. There are some dry camping areas around and access from the highway to the top and bottom of each of the loops shown on this map.