Kurobe Gorge is 90 minutes away from Toyama, taking JR Line to Uozo then switch to a local line to Unazuki Onsen. There is a direct train, but it takes longer and more expensive. At Uozo, go out of the station, turn left, enter the underpass to reach the local train station.
The gorge have 4 stations, but sadly you can't buy the ticket for the last station and expect to get down on all stations. You need to buy a ticket to your destination, and buy another ticket at the destination station to your next destination.
Most people get off at the last station, and tour group did stop at the second last station, but almost no one stop at the second station.
The gorge is a bit of a disappointment as Autumn colours haven't arrived yet. It's raining and we can't track too far into the mountain. Part of the train is open air, so it's more fun.