Ok ill start from the Top:
about 1 hour by bus from Aomori is a Ryokan called "Sukayu-onsen". You can get to Aomori by train and if you book the Ryokan youll get a free lift with a bus. There is a beautifull Mountain hike (around 4 hours). You can get the Bus to drop you off at the Cable car and than hike from the Top to the Onsen) the bus can take your lagguage).
The Ryokan itself cost a bit over 10000yen with food, but if you take the option without food its only 5000yen for a single room wich is reasonable. They have a small kitchen there!
The Onsen itself is huge with milky water and dark wood everywhere. The water tastes lemony and it is mixed bathing (so dont be shy). Definetly one of my top spots and my favourite onsen! I wrote on my webblog in german but you can see the pictures from there
here
From there you can head down towards Towada lake with a JR bus wich again has a nice little hike along the river and the lakeside is pleasant and quit.
again pictures
here
I then went to Akita wich was nice but not stunning
Next stop was Morioka wich is very easy to acces by train and has a old castle ruin. From there i went on a day trip to Hachimantai (i think only bus!) see
here
Next stop on the way down was Hiraizumi where there was once a "Buddist Paradise" with many temples. Today there are still some left and its a pleasant to spend a day there. It reminded me a bit of Nikko. Pics
here and you will also find somethings on wikipedia
There is a place called Naruko onsen where i stopped for a night, its a quite typical onsen town and only worth it if you havent seen a city like this before. Its also a bit of the track (try finding Osaki and than go to the left)
click
Next stop is Sendai wich is the biggest City in Tohoku (i think!) and nice for a few days. There are old castel ruins on the top of the hill and a "famous" cementry. Also try Guitan if you are there : )
click
However the real highlight in this Area is Matsushima bay, a bay with many small ilands with pine trees on it. It is one of Japans Top 3 sights and one of my favourites in Tohoku. see
here
From Sendai you can get to Akiu Onsen in about an hour (by bus). Another Onsen town with a nice small george for a short walk. Not much else to do this i definelty a place to relax a day. There is a huge and expensive Hotel wich is awesome insinde. Now heres the nice point: I got a recommodation from the tourist office to stay in their Bussines Hotel next door for 3500yen and i could use all the facillities of the monster hotel. Very nice Onsen!
click
You could now head out to the west coast to Haguro san, a holy mountain with a 2446 stairs approach (there is a bus) but its a bit far from the other things i described (aroudn 1 hour from tsuruoka) see.
here
My last Stop was Yamagata and Zao Onsen, wich was nice but not special.
I hope that was not to much information.....
My Top 3 are: Sukayu Onsen/Hakko san hike, Matsushima and Hiraizumi.
Ive got a map with all the points (or most of them)
here