We accidentally did it exactly right, too. The line was way too long when we got there, so we went to the park behind it and I sketched and we sat and people-watched.
Then we went to the park on the other side and took a bunch of pictures, and by then the line was very manageable. So we stood in the line as the group behind us WHISTLED the whole time. The. Whole. Time. As a group. Takes all kinds, I suppose.
Turns out the place was open way later than we thought, so we got to spend a lot of time there.
After that we went back to our neighborhood and bought all of the supplies we needed for a Spanish feast: tortilla de española, ham, more ham, cheese, more cheese, bread and wine, and we ate in our hotel room.
(click images for more detail)