26 x 1 3/8 rims/wheels were widely used in the 60s and 70s and new rims are available from Sun and often labeled as 650(A). (Someone may correct me so feed back is always welcome!) There are tires available and Google is your friend.

The Shimano hub, likely a 333, is okay but not stellar. I have one on a Nishiki and it is fine for leisurely rides around the neighborhood but YMMV. I am also a fan of IGHs so my opinions are biased.

As always, ride and enjoy. Things on old bikes can be persnickety but I enjoy that part of it.