which lens to carry for a trip to Madrid-Spain

Although this probably won't help you make a lens decision of those mentioned I can tell you of my experiences in Madrid and Toledo. Six years ago I traveled to both cities and continued on to spend a week in Morocco and the lens I used was a 20-35. I carried a bag full of other lenses but I can't remember using any of them.

I now have a FF camera and would use the 40mm and nothing else. I recommend traveling light and enjoy your trip. I bag of lenses gets pretty heavy after a while.

Recently I traveled with a Canon G1X and found it worked very well as a travel camera and the images are very high quality.