Iwate - possible routes (also includes a bit Akita, Fukushima and Niigata, but by train / car)

Relaxing Onsen  ⇒ 2 days, no riding

• Shinkansen from Hachinohe through Morioka to Tazawako, 1:15 h
• Rental car from Tazawako and into the onsen area → Actually bus turned out to be totally okay. 

Here a link to the actual stay and ride on Tazawako and on to Kakunodate. 

Route Morioka - Tono - Hiraizumi  ⇒ 4 days, 185 km

• Shinkansen from Hachinohe to Morioka (30 min)
• Ride bicycle along the valley from Morioka to Sendai
• See Garmin IWA Morioka - Hiraizumi - Matsushima - Sendai
• Ride along the river valley
• Day 1 - Morioka - Tono ⇒ 85 km (or less)
• See IWA Morioka - Hanamaki - Tono
• Relatively flat until km 60 (from 100 to 200 m), then 2 x 330 m
• Possibility to take train from km 40 (or also later) to Kashiwagidaira, from there a cycle road leads down to Tono 
• Accommodation
• Tono (2 nights)
• Day 2 - Tono ⇒ 42 km 
• See Garmin IWA Tono roundtrip
• Partially there is a cycle road into the valley of Tono
• Relatively flat
• Here a slightly shorter alternative trip through Tono valley: http://cycle-guide.panasonic.jp/special/yamahon/108.do
• Attractions
• Tono Valley
• Nice countryside, bicycle friendly
• Small villages
• 3 different open air village museums
• Onsen in Takamuro Suikoen
• Temples, Shrines...
• Fukusenji
• Kappabuchi Pond
• Day 3 & 4 - Tono - Hiraizumi ⇒ 56 km 
• Train from Tono back to Hanamaki, then riding along the valley to Hiraizumi
• See Garmin IWA Hanamaki - Hiraizumi 
• Gradually descending
• There is a cycle road from Hanamaki to Kitakami
• Attractions
• Hiraizumi UNESCO World Heritage
• Konjiki-do
• Monstu-ji (garden)
• Other temples
• Accommodation
• Hiraizumi (2 nights)

Here the link to the actual ride done.

Onwards to Aizuwakamatsu & Ouchijuku by train ⇒ 2 days, 9 km

• Day 1: Hiraizumi to Aizuwakamatsu ⇒ 9 km 
• Part 1: By bicycle: Hiraizumi - Ichinoseki station
• See Garmin IWA Hiraizumi - Ichinoseki
• Part 2: By train: Ichinoseki station to Aizuwakamatsu, by train, about 3 hours, one change of trains
• Accommodation: Aizuwakamatsu (2 days)
• Day 2: Aizuwakamatsu and Ouchijuku
• By rental car
• Attractions
• Aizuwakamatsu: Castle, Temples, Old houses...
• Ouchijuku Post Town
• There is a bike lane from about Amaya to Kitakata with some interruptions. Not sure it is useful.

Excusion to Tashirojima

• Possible excursion from Hiraizumi to Ishinomaki (either by train or bike) and then on the ferry to Tashirojima (cat island)

Onwards to Niigata and Sado Island by bus and ferry ⇒ 1 day, no riding

• Aizuwakamatsu to Niigata, by bus about 2 h 
• Niigata to Sado Island per ferry or jet foil, about 1  - 2.5 h