I would appreciate recommendations for a suitable city for overnight stop, about one-third of the way down. Last time we stayed at Salamanca and enjoyed it very much, but before committing I thought I would check to see whether any recommended alternatives? Also, the hotel in Salamanca we used last time, Vega Room Mate, seems fully booked for the month of September. Is there something happening then? Can you recommend a similar alternative hotel, preferably with parking? Many thanks

Don't know whether you would consider it comparable, but I was very happy with my stay here: https://www.salamancasuitestudios.com/en/

You might just go on a little further and spend the night at the Parador de Plasencia. It will be a long hot day of driving, about 1-1/2 hours beyond Salamanca, but doable.

www.parador.es/en/paradores/parador-de-plasencia

The Salamanca Fair, Fiesta de la Virgen de la Vega is held in September. The dates haven't been announced yet, but it should be around September 7-18

Segovia and Toledo appear to be about a third of way in a fairly straight line. Both are great but different. Everyone seems to rave about
Toledo as I do.
Segovia is known for its sweet old castle sticking out of one end of town:

https://www.google.com/search?q=sego...h=536&dpr=1.75