Need Advice for Kiso Valley

I have a few questions about Kiso Valley.

1. Since I've already plan to go to Takayama, Kanazawa and Kyoto, is it worth to go to Kiso Valley too?
2. Is it the same as Takayama, Kanazawa and Kyoto?
3. If I go there, is it possible to travel around Kiso Valley in half day?

Thank you very much for your help!

Do you mean to visit TSUMAGO/MAGOME?
If yes, I agree it is worth to visit.
http://japanpockettravelguide.weebly.com/chubu-area.html
http://www.kiso-magome.com/
But half day trip will be difficult/too rush although you don't mention which city will stay.

I hate to disagree, but I think it isn't worth the effort for a half day. Essentially Magome is pretty but not that different to the old part of Takayama (it is just that it is on a hill and has better views). Tsumago was not that interesting, and the walk isn't particularly interesting either. It is all worthwhile if you are going past it, but I wouldn't go out of my way for it. If you are at Takayama anyway, I think you might be better off spending a half day at Shirakawa, which will be closer to where you are.