Your interest in art has been evidenced in the many quizzes you have posted on DU over the years.
As you can imagine, the conundrum we face (albeit a happy one) is deciding what to see and do while there, given our time constraints. We both enjoy art, although neither of us are particularly educated in it. The Prado sounds promising, after my wife satisfies her desire for Gaudi architecture in Barcelona, and I thank you for the suggestion. El Escorial is a place I've wanted to see ever since being introduced to it in a college History course.
Your experience in the Pyranees sounds like something great trips are made of. I experienced something similar, I think, while on a solitary cross-country road trip back to the West Coast after delivering my oldest daughter to college in Philadelphia, although the quality of inspiration in the backstory was of a different nature than that which you described. It was a warm, late summer afternoon/early evening at Shiloh, on the banks of the Tennessee River. I arrived two hours before the park closed, and had the whole place to myself until the ranger finally ran me out and closed the gate. Having been something of a student of our Civil War, it proved something of an emotional experience for me.
I fully intend to enjoy Spain, and for all of the reasons you listed. 
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