Tararagawa suggestions

Would anyone know how to best enjoy Tararagawa Onsen in terms of nice accommodations, places to escape crowds, hiking and the like.
thanks!

The obvious choice would be to stay overnight at Takaragawa Onsen (there is only one ryokan). This gives you access to the baths in the evenings and mornings, when daytime visitors cannot enter.

However, although, I have not stayed there, frankly I don't like the atmosphere of that ryokan too much with bears living in mini cages and a rather weird collection of arbitrary stuff. You could consider staying at any other onsen ryokan in the Minakami area and visit Takaragawa Onsen as a daytime visitor. In order to avoid crowds, visit during the week outside of the busy travel seasons and/or early in the morning.