Altough Cuenca is a 2 1/2 hour drive from Madrid, it was the most ejoyable day trip on my recent visit to Spain.
Cuenca is a medieval city built by the Romans on a series of beautiful hills ( what a surprise). You will need your walking shoes. The Cathedral and it's Museum are splendid. They have an excellant Archaeology Museum right across the street from the Cathedral Museum. Don't miss the beautiful Casas Colgadas. Six hundred year old homes that hang from the side of cliffs with spectacular views. In one of them is a slightly upscale restaurant with fantastic food. Dinner for 4 with evrything from wine to dessert was $124.