It is possible to raft on Charyn river, you have to ask some reputable travel agency in Almaty.
This is the only part of the canyon directly accessible from the park gate. There are huge rock formations resembling castles, thus the name. You can see it from below, or you can walk on the upper flat the see it from above.
This is probably the best viewpoint in the whole area. You have the best view of the Valley of Castles below you, but you can also see deeper, otherwise inaccessible yellow canyon from a distance.
The majority of people visits the left bank of Charyn river, as the Valley of Castles is located here. If you have an all-terrain vehicle, you can however cross the bridge on the main road, go to Aksay village and visit this lookout, which will give you a different impression of the canyon.