Hola to all:
I just returned to the US last night. Had a wonderful trip in S. Poland, Brno, N. Portugal, and central Spain for a month. In Spain, I stayed in Burgos, Valladolid, and Madrid. My itinerary kept changing until the very last minute. For example, my heart was set for Logrono (after Burgos), which was highly recommended to me by David. However, due to difficult logistics, I have to save it for my next trip with a rental car. (Anyway, my heads off to him for giving me so much help and guidance!)
Burgos: very cute with a decent-sized old town. The vast majority of tourists were pilgrims for the camino. The Mirador is a must-go to get a panoramic view of the city. Valladolid is nice but not as charming as Burgos, but much less touristy. The pinchos were even better, too. I couldn't believe that I could eat that well for such reasonable prices.
About Madrid: I was apprehensive about major cities, but was relieved to find it less hectic and far cleaner & safer than Berlin, Rome, and Paris. I happily did a ton of apparel shopping, even though I had to swallow my pride in upsizing to XL or XXL from M/L (per Rick's suggestion about clothing hunting in Europe for Americans). I did hear a lot more English in Madrid than in Burgos and Valladolid combined.
The weather was mostly ok, with a few days of light rain. The temp was over 90F in Madrid, but it didn't feel stifling. In fact, 90F in Madrid was more bearable than 90F in where I live. So, now, my homework is going to be done on where to go in Spain in the first week of Sept 2019 (will spend second week in Menorca). By then, the weather will be much hotter.
Muchos Garcias to all of you. Happy travels!