We are buying the JR East Nagano Niigata Pass. Would appreciate advice on our following itinerary.
D1 : Narita Airport to Shinjuku hotel with N'ex (JR East Pass Day 1)
D2 : Stay Shinjuku
D3 : Shinjuku to Nozawa Onsen (Iiyama Station) (JR East Pass Day 2)
D4 to D9 : Nozawa Onsen
D9 : Nozawa Onsen to Snow Monkey Park to Nagano
D10 : Nagano to Matsumoto and back to Nagano (JR East Pass Day 3)
D11 : Nagano to Narita Airport Hotel (JR East Pass Day 4)
(1)Does the JR East Pass cover our above travels?
(2) For D9 to the Snow Monkey Park, is there any means of travel that we can use the JR East Pass?
(3) We are flexible for D9 and D10. Would appreciate if there are alternative sightseeing suggestions for D9 and D10.
For Days 9-10, it does not take all day to see the monkeys, and there are a couple of other hot spring places you could try. Plus Nagano City itself has some very nice sights, like the Togakushi Shrine and Zenkoji Temple. Matsumoto doesn't have that much surprisingly, but Matsumoto Castle is one of the best in Japan (and an original surviving one, not reconstructed fake). You could if you want see Togura Kamiyamada Onsen or Bessho Onsen in case you just can't get enough, though there are other sights there as well.
Another option from Matsumoto is a trip to Takayama, with a discounted bus ticket you can get with the pass (4500 yen round trip). However, it's 2½ hours one way which would not leave you with much time. Another idea is going partway down the same route to ride the Shin-Hotaka ropeway.
Pricey and time consuming, but if the weather is clear, you'd get a tremendous view.
Or maybe even Hakuba for more skiing.