The rapids are similar to the upper trinity but the better and faster. Flowing through a deep canyon on it's way out of the Trinity Alps Stuarts Fork has some of the best scenery of any run in the area.
The main section of rapids can be seen from the road past Trinity Alps Resort on a notable canyon bend. The main drop however is below this and harder to get a look at. Below the Resort rapids taper off and wood and willows become the game on the way down to the lake.
The put in is at Stuarts Fork Trail Head, one on the main trails in the Trinity Alps.
You can take out at the resort or down at Trinity Lake. The river flows when the upper trinity is over 700cfs. This run can be done quite high but it gets VERY fast and getting to the put in can be interesting.
There is also a class 4-5 run up in the wilderness from Deep Creek that's been ran quite a few times.