Skookum can be ridden in either direction. At each end it intersects, and is accessed from, Crosscut.
Riding counter-clockwise requires slightly more climbing at the start with more downhill towards the end, and riding clockwise is the opposite.
In my experience, counter-clockwise is a nice way to go. In this direction, the trail seemed to get slightly more technical as you went. The first half-mile or so is a relatively steady climb through nice maple forests on a south-facing slope. After that, the trail gradually turns and heads north, then west, putting you on a more shaded, sometimes damper north-facing aspect of the hill. The entire trail is rocky, but the rocky features in this section might be slightly more greasy and difficult to handle.
This is the rockiest, most difficult trail in the Britton Peak (a.k.a. Sugarbush) trail system, but it's worth the effort, even if your abilities require you to walk some sections.