Take exit 11 for Imlaystown and go south. At the stop sign at RT 526 (t intersection), make a left on 526 and the a quick right on Imlaystown Rd/Davis Station Road. Then make a left on Emleys Hill Rd (third left?) and maybe a mile up the road the park entrance is on your left.
Clayton is super fast and only a tad of roots but mainly just fast fast fast. Does get sandy and I would think right now some spots might be bad. The loop is kind of short (maybe 5 miles and some connecting trails) but there are fun downhills and some good log rides too.
I'll agree with everything STB said. I'd said it is a smaller version of Hartshorne. Strangely so!!!
I live just ten minutes from there but rarely go there. Just too small. I used to hammer a 5 mile figure-8 shaped loop in under 25 minutes. Lots of sweeping turned and changes in elevation. Like a roller-coaster.