Nice old things.
But the metal on metal of the braking discs produces a lot of heat,
so the grease gets toasted.
(If you’re going to service one, check the thermal rating on your grease. And Shimano makes a fine hub grease.)
Not for going down a lot of hills.
Depending on use, of course, get it serviced every thirty to sixty years, whether it needs it or not.
But not cheap.
Unless you want to keep the bike original, consider buying a new wheel, or even a new hub and have us build a wheel.
But then again, no one makes anything likes this anymore. Took even more time to make than to overhaul.
Been in there; done that.
Feel free to stick questions in the comments, and I’ll answer best I can. -dz