I recommend you to visit a place with a "neutral" accent, like Castilla or Madrid (no offense the rest), because it will be easier for you to understand that kind of standard accent, and your spanish will be easier to understand when you use it in other places. Madrid is very expensive, if you have not a reason for being here, you better avoid it and try Soria, Cuenca, Salamanca... not so fashion as Madrid but much cheaper. Enjoy!