Tohoku is large, mountainous and sparsely populated, and getting around in the boondocks can be time-consuming.
By train
Tohoku's main train artery is the TÅhoku Shinkansen æ±åæ°å¹¹ç· bullet train line on the east coast, connecting Tokyo to Aomori via Sendai, Fukushima, Morioka and Hachinohe, with spurs to Yamagata and Akita. An extension across the strait to Hakodate in Hokkaido is under construction, but will not open until 2015.
Outside the Shinkansen network, rural train services in Tohoku, known affectionately as donko, are slow and infrequent. It's not unusual to have waits of 2 or even 4 hours between trains, especially for services crossing the sparsely inhabited interior, and buses are often a faster option for intercity travel. The scenery along the twisty mountain routes can be stunning though.
While JR has a near-monopoly for connecting all major towns together, the stretch of ordinary track between Morioka and Aomori now belongs to a private company, and there are bits and pieces of private railways around the larger towns.
By bus
Especially for traveling west-east, buses are often a faster and sometimes even cheaper alternative to trains. For example, traveling by train from Morioka to Hirosaki takes around 4 hours even if you time your connection right, while a direct, hourly bus covers the same distance in just over 2. Buses usually leave from major train stations, and the largest operator is JR Bus Tohoku (http://www.jrbustohoku.co.jp/).
By car
Tohoku in particular north of Sendai is one of the few areas in Japan where you might want to rent a car. Rental car outlets are conveniently located near the train stations in the major cities, as this is the way local business travellers get around. When planning your trips, figure on your average travel speed on the road being around 60km/h. All sight-seeing spots have parking available, which is inexpensive as compared to the cities in the south. Note that in winter, many roads are closed entirely, and even major arteries can be temporarily blocked by heavy snowfall.
For long distance travel, the Tohoku Expressway more or less follows the route of the Shinkansen, but it's a solid 10 hours of driving for the 900 kilometers from Tokyo to Aomori. A good starting point for exploring Tohoku is Morioka, which can be reached by train from Tokyo in 2 1/2 hours on the Hayate or Komachi service.