Sukayu Onsen/酸ヶ湯温泉, traditional onsen, bus running from Aomori train station takes 1.5 hours until the Onsen. Before winter, one can also go to nearby Hakkoda Ropeway Sanroku Station/八甲田ロープウェー 山麓駅, and use the ropeway to a mountain. You can hike from there to the onsen. I got there end of November 2020, when the ropeway was already closed and there was snow - I walked to the onsen via road.