The Lame Horse Trail
could easily be divided into two halves.
The bottom (southern) half of the trail is characterized by lots of loose rocks, from small sizes to football sizes. The bottom half is steeper than the top and, added with the loose rocks, makes for a tough climb. Unfortunately, the loose rock takes a bit away from the descent as well. The downhill is still fun, but just not as fun as the top half.
The top (northern) half of the trail is characterized by ferns and dense forest. The trail is mostly smooth with the occasional root or rock drop/step. The ferns can get pretty tall and overgrown, and they might obscure your view of the trail in places, which adds to the intrigue of your downhill for sure. The uphill climb is still steep in places but nothing too extreme. The downhill direction is pretty sweet.
In all, I'd say the bottom half is probably deserving of a black diamond while the top half is deserving of a blue square. It's all rideable by a strong intermediate, but not without some max-effort moments.