Make sure to hit up Blackwater Bikes in town before hitting the park. They will hook you up with a map and tell you all about the trails in the area. They also had a pretty sweet selection of Cannondale and GT bikes. The trails here offer great technical climbs and descents as well as awesome scenery of the WV mountains.
From Charleston and Central West Virginia: Take I-79 N. to Rt. US 33 E at Weston. Follow 33 E to Harman WV, then take 32 N to Davis, WV.
http://www.singletracks.com/item.php?c=1&i=5636