How long do I need in Kamikochi

Hey all, I'm going to Takayama, Kamikochi, and Shirakawago for three days. I'm wondering if one day will be enough for Kamikochi. Here's my plan:
1.Leave from Tokyo for Kamikochi, stay a night there.
2.Leave for Takayama, stay a night.
3.Leave for Shirakawago, come back and stay a night in Takayama. Then leave for Kyoto the next day.

I'm also wondering if Shirakawago will be worth the visit in June with no snow. And can anyone give me the detail about the bus schedule from Takayama or Matsumoto to Kamikochi? I was searching for it but couldn't find anything. Thanks!

How long do I need in Kamikochi

It is up to you. Many people are content with just enjoying the view from the Kappa Bridge area. Others want to walk a few hours along the valley. And others want to make major trekking tours. A one day stay is enough if you are content with some short to medium walks.

I'm also wondering if Shirakawago will be worth the visit in June with no snow.

The snow is nice, but I find Shirakawago just as attractive during the warmer months of the year, when the forested mountains and rice fields are green.

And can anyone give me the detail about the bus schedule from Takayama or Matsumoto to Kamikochi?

From Matsumoto:
http://www.alpico.co.jp/access/route_k/honsen/info_e.html

From Takayama, take a bus to Hirayu and then another bus from there to Kamikochi. Buses are quite frequent.

Here are departures from Takayama to Hirayu:
http://www.nouhibus.co.jp/jikoku_pdf/08_03_0102.pdf

And Hirayu to Kamikochi:
http://www.nouhibus.co.jp/jikoku_pdf/2008kamikochi.pdf

The basic situation is explained here:
http://www.japan-guide.com/e/e6040.html

There is a direct bus from Takayama station to Kamikochi, I took it last autumn. I believe it runs just a couple of times a day: in the morning and early afternoon only: http://www.nouhibus.co.jp/jikoku_pdf/08_03_5001.pdf

If you decide to go there in the morning and return in the afternoon, I would suggest to alight at Taishokike pond (one of the first stops) and walk your way along the valley floor and make sure you get back at the bus terminal in time.
I would recommend to stay at least one night and explore the whole valley. We stayed two nights in different hotels and had an excellent time; really the highlight of my last trip. You can read my trip report here including the map of our walk and some of the photos I took: http://www.travelblog.org/Asia/Japan/Nagano/blog-256132.html

Thank you so much Uji and Kappa. I've decided to spend a night in Kamikochi. What I'll do is I'll leave from Tokyo to Takayama in the afternoon, take a bus to Kamikochi in the next morning and spend a night there. After that, I'll head back to Takayama and spend another night. In the next morning, I'll head to Shirakawago and back to Takayama in the late afternoon. Then I'll head to Kyoto in the following day. Appreciate your comment.

BTW Kappa your blog was awesome!

I'll leave from Tokyo to Takayama in the afternoon, take a bus to Kamikochi in the next morning and spend a night there.

The detour via Takayama is a waste of time and money. I recommend to head to Kamikochi directly from Tokyo (via Matsumoto) and then continue to Takayama and Shirakawago.

Ok, I will head straight to Matsumoto then to Kamikochi. Do you think 3 days would be enough to get a good feel for these 3 areas without being too tired and rushed? Thank you so much Uji. That helps alot.

Do you think 3 days would be enough to get a good feel for these 3 areas without being too tired and rushed?

I think three days is very close to the lower limit. An additional night in Takayama would not hurt:

day 1:
AM: travel to Kamikochi
PM: see Kamikochi

day 2:
AM: see Kamikochi
PM: travel to Takayama

day 3:
AM and PM: see Takayama

day 4:
AM and PM: see Shirakawago and continue to Kyoto. Instead of going back to Takayama, I recommend to travel from Shirakawago directly to Kyoto via Kanazawa. It saves you more than an hour of travel (and also some money):
http://www.japan-guide.com/e/e5953.html?aFROM=2158_5950