This hostel has been spot on. It's right by Aso Station (currently only served by bus), there's also a Lawson convenience store right next door. I didn't see inside the dorm but the double rooms are modern and spacious (unusual in Japan). There are plenty of showers, toilets and sink. Towel hire is only JPY 100. There's a variety of free teas, a well equipped kitchen and nice communal area. There's also a luggage store. The hostel has lots of handy information available for buses and maps of Mount Aso and the Kurokawa onsen, as well as the other attractions. Would definitely recommend!