Onsen Halloween Bonanza Gunma/Aomori/Tokyo

Hey Japan-Guiders,

My friend and I are planning an onsen trip through Gunma and Aomori with a Halloween finale in Tokyo which we are pretty excited about since that is the best combination of everything there is, but we have a few questions which we have not yet been able to find reliable answers to online.

We have narrowed down what we think are the most scenic/interesting onsens in the area in this 11-day itinerary:
Arrive in Tokyo on October 21 (1 day)
Gunma: Takaragawa (2 days), Kusatsu (1 day)
Aomori: Aoni Onsen (2 days), Kuroyu Onsen (2 days)
Tokyo (3 days) for Halloween weekend!

Our questions:

1. Is there an easy route on public transportation from Takaragawa to Kusatsu? We are assuming that renting a car for this portion would make the most sense.

2. Since we want to travel from Gunma to Aomori, what is the best route on public transportation (trains/busses) for getting from Kusatsu to Aoni Onsen and about how long will it take? If it is too long to do in one day, we are also considering the option of going to Tokyo first and taking an overnight bus to the Aoni Onsen area so that we arrive there the next morning, not sure if that possibility exists. Renting a car and making the trip could also work, but that does seem like a long way to drive on the other side of the road :p

3. From Aoni Onsen we will travel to Nyuto Onsen (Kuroyu)- Is this possible to do through public transportation or only by car? If there is a practical way, could someone advise on the route by public transport and about how long it will take?

4. Halloween this year falls on a Monday, and we would like to be part of the Shibuya Halloween craziness- will the peak events happen on the Saturday/Sunday before or on Monday?

Thank guys! The Japan-Guide community has always given great advice in our previous trips to Japan, and we appreciate the help. Have a happy Hall-onsen-een!

...I will workshop that pun.

I applaud your punny attempt.

I would just spend a day at Takaragawa and two in Kusatsu, since there is a lot more to do in Kusatsu (unless you're planning outdoor sports type things in Minakami, in which case just ignore that).

Basically getting around the more rural areas mostly mean going through bigger cities for your public transportation, while driving can be more direct...but not always! Between Minakami and Kusatsu, you'd take the train down to Shibukawa then transfer there and go to Kusatsu. But in those areas because of the mountain roads, I'd say really the time isn't terribly different between the train and driving. It'll take maybe 2+ hours either way.

However heading up to Aomori, it'd probably be faster to go through Tokyo. I've actually driven Gunma to Aomori before. It's a beautiful trip! But we stopped several times along the way. Going straight north as fast as you could would be exhausting.