I was reading the inclusions and noted that a bit of Tobu is included
- Reserved seats in ordinary cars of the following express trains with through operations between JR EAST and Tobu Railway lines: Nikko, Kinugawa, and SPACIA Kinugawa trains.
- You can also use regular trains (including rapid trains) from Shimo-imaichi to Tobu-nikko and Kinugawa-onsen on the Tobu Railway line.
Between Kurihashi and Shimo-imaichi, you can only use limited express trains that run through to Tobu Railway. *
- The only limited express trains you can use with the JR TOKYO Wide Pass are through trains from JR lines to Tobu Railway lines. You cannot use limited express trains whose first and last stations are Tobu Railway stations.
If you do go to Nikko, you could potentially also take the Spacia X for a bit out of pocket
New Limited Express Spacia X on Tobu Line Asakusa (Tokyo)-Nikko/Kinugawa Onsen . Spacia X may not be currently covered by the pass (Spacia's the older train while Spacia X is the 2023 new train). The Tokyo wide pass does seem like it'd cover the Tobu Tobu-Nikko to Tobu Kinugawa Onsen and the Tobu World Square (
miniature land which your kids might be past age sweet spot but possibly not, depending on their interests) stop right before Kinugawa Onsen.