Trip to Tateyama Alphine route

I'm planning to travel with my 2 brothers to Tateyama Alphine route via Nagano on early September 2016 . My questions are:-

1. How much the ticket cost per person for a one way trip from Nagano to Toyama? What does the tickets cover? Do we need to book the ticket or just walk-in purchase?

2. How long the trip would take? Is it possible to complete in a day?

3. If we end the trip at Toyama, what are the available public transport that we can take to get back to Tokyo? Please stated the option and fare if possible.

Thank you for attenion.

1. How much the ticket cost per person for a one way trip from Nagano to Toyama?

Along the Alpen Route? You will first have to take a bus from nagano to Ogizawa which is not part of the Alpen Route. The one way fare is 2600 yen.

From Ogizawa you can buy a ticket for travel along the Alpen Route for 9490 yen one way:
https://www.alpen-route.com/en/transportation/timetable-fares

What does the tickets cover?

A one way trip along the route over a time period of up to five days. Backtracking is not allowed.

Do we need to book the ticket or just walk-in purchase?

Walk-in.

2. How long the trip would take? Is it possible to complete in a day?

Yes, it is possible in a day.

Timetable for the Nagano-Ogizawa bus:
http://www.alpico.co.jp/access/express/nagano_omachi/

Timetable for the Alpen Route for 2015 (likely to be similar to 2016):
http://www.alpen-route.com/en/transportation/timetable-fares

If we end the trip at Toyama, what are the available public transport that we can take to get back to Tokyo?

Shinkansen (2 hours, about 13,000 yen one way)
Highway bus (7 hours overnight, from 3800 yen one way)
Airplane (about 3 hours, from 12,000 yen one way)

If we end the trip at Toyama, what are the available public transport that we can take to get back to Tokyo?

Shinkansen (2 hours, about 13,000 yen one way)
Highway bus (7 hours overnight, from 3800 yen one way)
Airplane (about 3 hours, from 12,000 yen one way)

Question:-
If I choose Shinkasen, I plan to buy a JR East pass, but the pass is not valid from Toyama station. The nearby station will be Joetsu-Myoko Station. What is the available transport from Toyama to Joetsu-Myoko Station?

What is the available transport from Toyama to Joetsu-Myoko Station?

Shinkansen. The supplement cost will be around 4500-5000 yen.