First time in Japan: itinerary doable

Hello everyone,

in October I will be in Japan for the first time in my life.
I prepared an itinerary for a month. Could you please tell me if this is doable or if it's too full or if you've got any suggestions:

30. September arrival in the evening Tokyo - Haneda
1.-3. October stay in Tokyo
4. Tokyo - Kamakura
5. Kamakura - Hakone
6. Hakone - Nikko (I wonder if I should better do daytrips from Tokyo?)
7. Nikko - Yamadera - Sendai
8. Sendai Daytrip Matsushima
9. Sendai - Aomori Daytrip Osorezan
10. Aomori - Nyutu Onsen (actually I just want to stay one night in an onsen ryokan so if you've got any better suggestions...)
11. Nyutu Onsen - Dewa Sanzan (as one of the shrines is already closed, I'm not quite sure if I should go to Dewa Sanzan)
12. Dewa Sanzan - Nagano
13. Nagano Daytrip to Yamanouchi (snow monkey resort)
14. Nagano - Takayama
15. Takayama
16. Takayama- Kiso Valley - Osaka
17. Osaka
18. Osaka - Himeji - Hiroshima
19. Daytrip Miyajima
21. Hiroshima - Nara
22. Nara - Ise
23. Ise -Mount Koya
24. Mount Koya - Kumano Kodo (go hiking)
25. Kumano Kodo
26. Kumano Kodo - Kyoto
27. -30. Kyoto

I think I will buy a 21 Day JR Pass.
Maybe I should also mention that I want to keep it low budget, because I'm backpacking. So if you've got any tips, suggestions, places I've missed etc. please tell me!

Unless you specifically wish to overnight in Kamakura, I recommend to visit the town in a side trip from Tokyo.

Hakone - Nikko (I wonder if I should better do daytrips from Tokyo?)

It depends on how much you want to see. If you don't want to see that much, indeed it is possible to visit Hakone and Nikko in day trips from Tokyo.

10. Aomori - Nyutu Onsen (actually I just want to stay one night in an onsen ryokan so if you've got any better suggestions...)

It is spelled Nyuto Onsen! It is one of the best rustic onsen in Japan.

11. Nyutu Onsen - Dewa Sanzan (as one of the shrines is already closed, I'm not quite sure if I should go to Dewa Sanzan)
12. Dewa Sanzan - Nagano

Dewa Sanzan is time-consuming to access and time-consuming to get around. Indeed, I recommend to consider dropping it if you have limited time.

16. Takayama- Kiso Valley - Osaka

It is a busy day, but possible.

21. Hiroshima - Nara
22. Nara - Ise
23. Ise -Mount Koya
24. Mount Koya - Kumano Kodo (go hiking)
25. Kumano Kodo
26. Kumano Kodo - Kyoto

The itinerary in general is very intensive, but in particular these final days are very intensive. You seem to change accommodations on a daily basis and will be sitting on trains for a considerable time of your days. But it depends on the person. Some energetic people who love a fast pace of travel may be able to enjoy it. But for the average traveler, I think it is too intensive.

I would break some things into day trips to save you some time moving around accommodations.

Kamakura and Hakone work well as day trips from Tokyo. Nikko you can do as well, but it also works on the way to Sendai.

I would change part of your trip around to cut down on train time.

Take Dewa Sanzan out, and perhaps do the rest like this
11. Nyuto Onsen - Nagano
12. Nagano day trip to Yamanouchi
13. Nagano - Takayama
14. Takayama
15. Takayama - Nagoya
16. Nagoya - Kiso Valley day trip
17. Nagoya - Ise
18. Ise - Kii Katsuura (base for Kumano Kodo hiking)
19. Kumano Kodo
20. Kumano Kodo - Mt. Koya
21. Mt. Koya - Osaka
22. Osaka
23. Osaka - Nara day trip
24. Osaka - Himeji - Hiroshima
25. Hiroshima/Miyajima
26. Hiroshima - Kyoto
27-30. Kyoto

Thank you very much for your answers.
I will leave out Dewa Sanzan then. Hopefully I'll come back sometime.
And I will do Hakone and Kamakura as sidetrips.
The point in doing the Kumano hiking in the end was that I can't travel with the railpass there I've I got it right.
So this would save me money. But I'll think about it.
Sorry for the spelling mistake, I didnt't pay enough attention...

A 14 day JR pass would pay off, and you could plan it to end on the day you arrive in Kumano (if arriving from Ise you'll take mostly JR trains to get there). Then from Osaka to Himeji and onwards you can use the Kansai Hiroshima Area Pass: http://www.japan-guide.com/e/e2361_kansai_hiroshima.html

The total for those two passes is only 40 yen more than a 21 day pass.

Oh great, thank you!
That sounds like a really good alternative, I wouldn't need to spend my whole time on trains!

Oh great, thank you!
That sounds like a really good alternative, I wouldn't need to spend my whole time on trains!