Day trip suggestions from Madrid as base?

Thank you for the suggestions! You are correct we won’t have a car; train or bus access only. Bare with me, just learning Spanish! Saludos!

I recommend spending at least one night in Toledo rather than seeing it as a day trip. Toledo is beautiful at night while illuminated and much quieter after the tour buses have left. I remember sitting outside at night in Place Zocodover. There were many families enjoying the evening with their little children riding their bikes. It was such a pleasant and enjoyable experience not to be surrounded by tourists and tour buses.

Our itinerary was the same as yours except we stayed overnight in Toledo. BTW, we really enjoyed Malaga, a much under-rated city.

You could possibly combine Ávila with Salamanca for a day trip. To me, Ávila is only worth a couple hours and is nice to walk around. A good place to get a great photo of the city wall is from the Cuatro Postes overlook. Cuenca might also be an option. Other than the Real Monasterio de San Lorenzo de El Escorial and its pantheon of kings and queens, the town has little else to offer, so if you’re not interested in it, I’d skip the town and spend your time elsewhere.

I'm one who found Avila disappointing and not really worth the effort by public transportation. A stop-by visit if you had a car would be a different matter.

Salamanca has a large, handsome historic district and can fill a day. There are tours of the university.

Toledo is definitely worth an overnight, but many folks enjoy a day trip there. I'd at least recommend planning for a long day in Toledo. There are some lovely small mudejar buildings to visit as well as the more well-known sights. The large hilltop historic center is very atmospheric, and it is hilly.

There's more to see in Segovia than just the stunning aqueduct, so it, too, can fill a day.

Alcala de Henares is a great option because it's accessible by very frequent commuter trains. It doesn't require a great deal of planning ahead beyond checking for info on the historical sights there.

Cuenca is trickier. It has a charming hilltop historic center and two nice, smallish modern-art museums. I liked it a lot and spent multiple nights there. But it's a long way from Madrid and a viable day trip only if you spring for a ticket on the AVE, which takes just 54 minutes. The AVE fare to Cuenca can be quite pricey if you don't buy early enough to snag Promo tickets. You won't run into that degree of price risk for the other potential trips suggested in this thread.

Although Toledo is also served by fast trains, the ticket prices aren't any more expensive if you buy them right before you travel. There is, however, some risk that trains to and from Toledo might sell out, so do be careful to pin down your return ticket from Toledo ahead of time.

We like history and hiking!

You're in luck, because the Madrid area has some of the best hiking in Spain.

I know friends of mine from Madrid typically head to the Sierra de Guadarrama National Park, just 1 hr north of the city, for their nature/hiking fix. The Sierra de Guadarrama is densely forested mountain range of mixed pine an oak, dotted with rock formations and rivers. The C8 local railway line reaches the mountain village of Cercedilla, from where it is possible to access some of the hiking trails of the Sierra de Guadarrama.

Here's the official website of the National Park: https://www.parquenacionalsierraguadarrama.es/en/

I have not been to other towns mentioned above except Salamanca. It's beautiful and I spent one night there (had most of my luggage stored at my Madrid hotel).

Burgos is also nice, but it's further away.