If you are coming to Valencia and you want a great apartment in a perfect location then try to stay in Daniels apartment in Ruzaffa. The apartment has everything you need for a long weekend or an extended stay. We stayed for 8 nights and we found the situation in Ruzaffa really enhanced our stay and we will not hesitate to go back. The apartment is really well equipped and the beds are very comfortable. Situated on the third floor you have a good outlook onto a very nice part of Ruzaffa and with the windows and balcony doors open you can get very good ventilation which meant that we didn't have to use the aircon once!
Be sure to read Daniels manual for great recommendations for dining and activities. I would also like to recommend a place called Casa Montana for tapas.... http://www.emilianobodega.com/carta-de-tapas/ ....very popular so best to book ahead.
The centre is easily reached, walking about 15mins or cycling via extensive well connected cycle routes which pass by the front door of the apartment and has the Valensibi bikes close at hand. Valencia has a very good public transport system and taxis are also cheap and plentiful so getting around is very easy. If you come by car as we did, you can use the parking garage in the adjacent street until you find a free space on the streets nearby where there is free parking.
The apartment is very clean and the host makes you feel very welcome. We will come again if we can.