Alpine route last departure from ogizawa

Hi, I will be using the alpine route option ticket and doing a one day travelling, then I'm planning to go back to tokyo directly at night. When is the last transportation available from ogizawa to shinano omachi? Because I'll be taking the train from jr shinano omachi to tokyo then.

Thank you!

I will be using the alpine route option ticket and doing a one day travelling,
then I'm planning to go back to Tokyo directly at night.

Just to make sure: are you aware that this ticket does not allow you to turn back?
When will you travel?
In which area of Tokyo is your destination located?

Tateyama Kurobe Alpine Route: Timetables
http://www.alpen-route.com/media/access/timetable/timetable201603.pdf

[From 16 April through 3 November 2016]

The last bus connection to Shinano-Omachi:
Kurobe Dam (16:35)
| [tunnel trolley bus]
(16:51) Ogizawa (17:00)
| [local bus]
(17:35) Shinano-Omachi.

JR connections from Shinano-Omachi Station to Tokyo Station:
Route A.
The one-way cost: 7450 to 7850 yen (depending on days) per adult passenger.
Shinano-Omachi (17:58)
| [JR: Local train for Matsumoto]
(18:56) Matsumoto (19:21)
| [JR: Limited Express Azusa 34 for Shinjuku]
(22:07) Shinjuku (22:15)
| [JR Chuo Line: Rapid train for Tokyo]
(22:28) Tokyo.
Route B.
The one-way cost: 9620 to 10020 yen (depending on days) per adult passenger.
((Same as A. until Matsumoto))
Matsumoto (19:14)
| [JR: Local train for Nagano]
(20:26) Nagano (20:55)
| [JR Hokuriku Shinkansen: Kagayaki 516(#) for Tokyo]
(22:20) Tokyo.
#: Seat reservation is mandatory.