Canyons is a 5.5 mile trail that forms the backbone of the trail network on the southeast/plains side of CGSP. Canyons is tough to describe because it has 5 distinct sections, each with it's own characteristics. I'll describe the sections going from northwest to southeast, the direction I rode them.
#1, this .6 mile section of singletrack begins at the parking area near the dam on the southeast side of the Crystal Springs Reservoir, and eventually connects to Mahogany. Near the dam, the tail loses about 100ft of elevation on a series of tight switchbacks. The granite gravel in the corners is pretty loose and the consequences of overshooting are on the high side, so you really need to slide the rear end abound. Sliding the front end will make you very uncomfortable. After the switchbacks the trail bobs and weaves across the side hill of the canyon, until you reach another set of switchbacks that drop you another 100ft down to the creek, and the intersection with Mahogany. CGSP mark this trail as "advanced".
#2 From the Mahogany intersection, this .7 mile section of singletrack connects to both ends of Middle Kingdom, the Crystal Ridge trail, and eventually to the Cliffhanger trail at the northeast end of Crystal Reservoir. The trail is the typically narrow granite gravel singletrack with occasional short/small rocky challenges. There is very little elevation change, on this trail so it's a pretty easy ride. The trail is a little to narrow to look around while rides, so be sure to stop and admire the odd slabs of rock pointed skyward, which is characteristic of CGSP. The maps mark this trail as "intermediate".
#3 Heading SE from the Cliffhanger intersection, this section of Canyons hugs the north side of Crystal Reservoir for 1.2 miles, until the second intersection with Blue's Cruz. You'll see really cool pictures of this section of trail overhanging the reservoir. The views are really nice. While there are a few technical obstacles and some high consequence bits of trail, the two never seem to happen simultaneously, leaving this pretty ride-able for most riders. There were a couple of sections that have clearly wash out in the past. These sections were in pretty good repair for my ride, but they could really change the risk/reward complexion of the trail, so be alert. The maps mark this trail as "advanced".
#4 Heading SE of Blue's Cruz the trail gets more technical as is moves away from the reservoir. I enjoyed most of the steep/challenging technical obstacles of the first .5 mile that I rode, but there we a couple of very steep sections that clearly couldn't hold any the intended granite gravel on the trail surface (the embedded mats were only pseudo-effective), forcing hike-a-bike. Unfortunately, I had to turn back due to time constraints (missing 2/3 of this section of Canyons). It appears that I was about to hit more hike-a-bike -> I've heard others complain about this. The maps mark this trail as "expert".
#5 I didn't ride the far SE section of trail. The maps mark this trail as "intermediate".