How to get to Kinugawa Onsen Koen Iwaburo?

Can I get to Kinugawa Onsen Koen Iwaburo using 2 day Nikko pass?

Yes, you can get there using Tobu 2-Day Nikko Pass.

Kinugawa Park (, which is actually not "Kinugawa Onsen" Park,)
is just near Kinugawa-koen Station,
which is between Kinugawa-onsen and Shin-fujiwara Stations on Tobu Kinugawa Line.

- Tobu Railway: Route Map
http://www.tobu.co.jp/foreign/en/using/route.html
- japan-guide.com: Tobu Nikko Passes
http://www.japan-guide.com/e/e2358_002.html

Please be careful of days when the Iwaburo [Open-Air Rock Bath] facility is closed.
Its closed days during the next six months (until 20 March 2017)
will be Tuesdays and the 30th and the 31st of December 2016.
Also, smoking is prohibited inside the bath facility.

From Tobu-nikko Station,
you have to change trains at Shimo-imaichi to get to Kinugawa-koen Station,
except when you take a direct Rapid "Aizu Mount Express" (Tobu-nikko {11:37} -- {12:14} Kinugawa-koen).

Thanks so much for your info