I am planning a ski trip and I think the JR East Tohoku pass will pay off but because it doesn't cover Nagano how do I pay for the additional leg?
The plan is this;
12/2/20 Tokyo to Zao Onsen
17/2/20 Zao Onsen to Tokyo
18/2/20 Tokyo to Shiga Kogen
If you want to use the Tohoku Area Pass, it can take you to Zao but only part of the way to get to Shiga Kogen - only up to Sakudaita Stn. So when you return to Tokyo after seeing Zao, just go to the JR office and buy a bullet train ticket for the uncovered portion - by a Hakutaka train for example it would be ¥2860 for the 20 minute ride. From Nagano Stn you'll need to pay for the bus or non-JR train the rest of the way to Shiga Kogen.