Spain-Best Small Towns Central to Transport

Spain is big and very diverse. There is really nowhere to stay in one spot to see it all. Also, chances are, if it is on a tourism forum, it isn't going to be terribly 'untouristy'. With 6 weeks, I would want to move at least once if not 4 times but then I don't see the point of incurring the travel costs and time involved to do a bunch of day trips. Toledo and Cordoba are touristy cities - during the day - but nighttime brings a whole different vibe. They aren't alone for having a totally different vibe when the buses depart.
That being said, it is not my vacation. I would still advise considering a region rather than the entire country. With no more details than provided, I would stick a pin into the map and then using rome2rio, renfe and Alsa bus maps, look to see where I can go from there.
(also remember that 'Spanish' isn't going to be the prime language in some regions - particularly in small towns).

I agree with Maria, don't choose a central point (unless it's Madrid and every side destination you choose is on the AVE line).
Personally, I'd rather decide on perhaps 4 regional "hubs" to fan out from.

By regions, I mean for example Galicia, Basque, Catalonia, Andalusia, etc.

FYI, 3 of those 4 have their own language, along with Spanish... enjoy!

Or look at it this way; Spain is almost the size of Texas. Would anyone choose just one base to explore the whole state?

Happy Travels!

I am open to “moving” a few times within that time frame or to stay the duration. Suggestions for small towns to “live” in for more immersive experience? We have spent time in Madrid, Segovia, Toledo, El Escorial.

Thanks

If you are looking to "live" in one town/city, I assume you will be spending the 80-90% of your time there. Well if I was on vacation and I would be confined to only one town/city, I would go with Madrid, it has the most to keep me busy on a day-to-day basis for a month, and is literally the central hub of transportation in Spain.

I’ll assume you’ll have a car for at least part of the time. I’ll go out on a limb here and suggest Zamora as a smaller city with access to a number of locations. It is less touristy than many places, so you could easily practice your Spanish. It is 2.5 hours from Madrid and a little over an hour from both Leon and Salamanca. If you like castles there are ones in Coca, Medina del Campo, Arevalo, Ponferrada, Puebla de Sanabria, and Valencia de Don Juan. Most of those towns are nice to walk around. Astorga is nice for a short visit. The treaty of Tordesillas was signed in the nearby town with the same name, and Convent Santa Clara in Tordesillas is nice for a visit. Burgos is a couple hours away and Segovia is a little closer than that. In Spain, once you get away from the main tourist sites, there are many places where people do not speak English. Also, one leg of the Camino de Santiago passes through Zamora up to Leon and over to Astorga if you felt inclined to walk part of it. It really depends on what you want to do with your time.