Annadel is a great trail system with over 35 miles of trails, much of which is singletrack. The trails are generally buffed singletrack but there are some rocky/ technical sections as well (Rough Go and Cobblestone). This route is somewhere around 25 miles and if you need to be in pretty good shape to ride it as it involves at least 2500' of climbing.
The long route around Annadel is the one I've taken on the last few rides there. You take Channel Drive to W. Richardson. Then either take Two Quarry to Marsh or stay on Richardson to South Burma and take South Burma to Marsh. Stay on Marsh to Lawndale and the take Lawndale down, down, down to Lawndale drive. Turn right on the pavement and right again when the road Ys and then keep an eye out for a trailhead on the right have side. Go up Schultz to Upper Steve's then follow U. Steve's around to Marsh. Go right on Marsh and stay on it until you hit South Burma. Take S. Burma to Richardson and then right turn uphill on Richardson to North Burma. Go down (Yippee!) N. Burma but don't miss the turnoff for Live Oak. Take Live Oak back around to Orchard and then take Orchard to Cobblestone. Take Cobblestone back to where you parked.
If that doesn't wear you out you can try taking Live Oak all the way to Rough Go instead of Orchard then descending Spring Creek and climbing out Rough Go to Cobblestone.
This map was found originally on the Annadel State Park Brochure PDF but it was in 4 parts and impossible to read on a computer and on little use even to print out. I've edited it a bit, merged the 4 pages so hopefully you will find it more useful.
You will want the bigger picture for it to be useful. Green dashed lines are singletrack, red dashed lines are fireroad otherwise everything should be self explanatory.