Tateyama Kurobe from Nagano to Toyama

Hi,
I'm planning to visit Tateyama Kurobe next summer, start from Nagano, stay 1 night on Murodo, and back down to Toyama the next day.

How's the best way in buying the tickets? Is it correct that I buy one way ticket from Nagano to Toyama all the way? Can it be valid for 2 days?

Or should I buy one way ticket from Nagano to Murodo for 1 day + one way ticket from Murodo to Toyama?

And since I will go with 5 other family member, should I book in advance or on the counter?
Thank you for answering.

How's the best way in buying the tickets? Is it correct that I buy one way ticket from Nagano to Toyama all the way? Can it be valid for 2 days?

Tickets are valid for up to 5 days. If you can buy one all the way from Nagano, that will be most convenient. Otherwise, pay for the bus to Ogizawa separately and purchase a ticket from Ogizawa to Toyama.

Or should I buy one way ticket from Nagano to Murodo for 1 day + one way ticket from Murodo to Toyama?

No, that is not necessary.

And since I will go with 5 other family member, should I book in advance or on the counter?

If you buy in advance, you can reserve a specific bus departure at Ogizawa, which will come handy on busy days. But advance reservations reduce your flexibility. It depends on personal preference.

Thank you so much for your answer Uji. It really helps me :)