I've been living in Europe for 30 years now. This is all definitely good advice. Particularly with global warming, July in Central to Southern Europe is really hot.

In an earlier life segment I traveled around Europe doing sport and alpine climbing. I highly recommend climbing and hiking locations, even if you don't climb (definitely try some hiking). Climbing/hiking is not a sport for the wealthy (or it didn't used to be), so there are plenty of cheap hotels and local food.

You'll get to see the beautiful European countryside. You'll experience real European culture (not that city-folk aren't real, but going to get a Sacher Torte at the Sacher doesn't exactly overwhelm you with Austrian culture). It is everything other than a tourist trap.

One point I will concede. You need time. Spain is huge. Getting out of the big cities takes time. If you don't have time, well then you're going to see St. Mark's and the Rialto bridge in Venice, and that's about it. Same for many of the other big cities.

If you have the time, however, just get out of the cities. Railpasses are cheap. You see more than from the autobahn, and no one has to drive.