Happygrandma has wanted to go to Spain with Happykid for years. Happydad can’t get away from work, but I can. 
We are hoping for three or four days in Madrid, and then somewhere else - Sevilla/Cordoba/Granada? Barcelona?
Happygrandma is pretty familiar with Madrid, so other than paying for the hop-on-hop-off bus tour, we will just do that city all on our own. So far all the escorted trips to Sevilla/Cordoba/Granada just look exhausting. Hours of walking and umpteen cathedrals/castles/museums. Would do-it-ourselves-by-rail make sense? Do we bail on that trio, and head to Barcelona instead? Oh, and we need at least one live theater performance somewhere for Happykid the lighting designer to claim on her taxes next year as “research” 
Barcelona is beautiful! Sagrada Familia is breathtaking.
Figure out train tickets before you go. And it’s not easy. You’ll need either a certain type of CC (which we didn’t have) or a PayPal account.
I printed out the instructions from google (pages long) to finally figure it out. You click on English on their train reservation site and go merrily along and then all of a sudden it turns to Spanish (never to see English again–hence the need for instructions printed out beforehand). You pick seats etc first and THEN make the reservation (backward from like making plane reservations). But train travel in Spain is wonderful. Clean, fast.
Barcelona is one of the prettiest places I’ve been. The Sagrada Familia is like a fairy sand castle in the middle of the city. Again, make reservations ahead of time for a guided tour. Otherwise you won’t know what you are looking at and the line to get in can wrap around the entire city block. The tour is by audio headsets so you can hear pretty well even in the crowd. Don’t be late!!!
Gaudi park is also great but get tickets ahead of time to go into the main parts. Still fun but we missed getting in–now we have an excuse to go back!
So many thieves, robbers, pickpockets in Barcelona - my kids didn’t feel safe there this week. Left the AirBnB just off Las Ramblas after 1 night (paid for 3) for a hotel where the area felt less crazy.
Las Ramblas is pickpocket heaven for sure. Spain has a ton of pickpockets–we always wear money belts under clothes, my purse had a lock on it and metal mesh.
Train to Barcelona. Have advanced reservations for Sagrada Familia or you won’t be able to tour inside. Go to Montjuic using the teleférico.
Plan on good shoes and very light clothing. It will be horrendously hot in Madrid in July and extremely warm in Barcelona.
If you don’t have good “light” clothing, your first stop will be El Corte Ingles department store for their annual clothing sale. The clothing is beautiful and light and very reasonably priced. Basically, its a Macy’s/Target/Food store combined. They accept many debit/credit cards.
Don’t go to an ATM by yourself, and be sure to wear cross body purses.
Have a great time!!!
Barcelona is great. I would always go there. I would never stay in the Barri Gotic (which is the extremely touristy area on the right side of Las Ramblas coming up from the port).
A few years ago, on a similar trip, we spent a couple of days in Grenada and loved it (although it was super hot in July). The main attraction is the Alhambra, which you can see perfectly well without a guide. Also Federico Garcia Lorca’s house, and the city’s Arab quarter. And the Arab baths, which were lovely and fun.
We loved the Torre Catalunya, just a few steps from the train station.
No, it wasn’t at Las Ramblas but it was central to anything moving and appeared to be quite safe!
Spain in July is going to hot. I might suggest staying in Madrid and doing day trips or an overnight to Toledo. From Madrid you can do a day trip to Segovia as well as to the Escorial. Although I love Barcelona and have been there several times, I might suggest heading instead to Avila and Salamanca instead. You do have to be careful of pickpockets in Madrid as well as in Barcelona. I have a friend whose daughter was doing a summer study in Madrid. Her bag was slit as she was walking down the street. When my friends visited, her husband was attempted to be pickpocketed on the subway in Madrid but he was able to literally shove the guy halfway down the subway car.
^^
I would not go south of Madrid because of the heat.
We were in Barcelona in July and it was hot, but bearable. We rented an apartment on Placa Catalunya and highly recommend this location - just make sure there is A/C, you can’t leave windows open at night because it may be noisy.
We rented a car to go to the Dali museum and then spent the night in Begur on the coast.
How about San Sebastian?
Right now Barcelona is only still an option because of Sagrada Familia. Otherwise, nothing more than three hours or so by rail from Madrid.
A road trip out of Madrid through some piece of interesting countryside with places to stop for a winery tour or a good snack en route to someplace no more than 4 hrs drive away could also work.
Madrid is one of the least interesting cities in Spain. I’d spend as little time there as possible.
H and I did Spain a few summers ago. It will be hot. But a dry heat. And no matter what anyone says, humid heat is far worse.
Anyway, we traveled by train and then air between Seville and Barcelona. We went from Madrid to Sevilla to Grenada to Barcelona back to Madrid. We did air when it was faster and about the same price.
Get advanced tickets for anything you want to see. The Alhambra, Alchazar, Gaudi locations. We did get a private English tour at the Alhambra. It was well worth the extra money, which seems to me was not a great amount. At the Alchazar you eiither get or pay for earphones. Again, if you have to pay for it, get it. It is worth it.
We stayed in boutique hotels and they were all wonderful. Not big rooms, but quaint with ambience, clean, great breakfasts and overall just nice.
Maybe head to the coasts for the beaches.