Zaragoza & lonrongo - nov 4 & 5& 6. Recommendations needed.
I apologize, I don't know the second place you mention.
As far as I know Zaragoza wouldn't be considered the center of any wine region (not that I know all of them). The places I think of as centers are Vitoria-Gastiez, which is quite a way NW of Zaragoza, and Valdepenas, which is as far or farther SSW. I know Penafiel, near Valladolid, west of Zaragoza, has a wine museum - not sure if it's considered the center of the Ribera de Duero area or just part of it.
The only places we found that offered drop-in tastings/tours were in Jerez, down past Sevilla, where they make Sherry. Everywhere else you have to call ahead a day or two in advance to let them know you're coming. The wine museums are typically old wineries and should all have a wine bar where you can try the local wines - their hours can be limited though, so a call ahead before visiting isn't a bad idea.