If youâ??re going to be in Cadiz, Iâ??d recommend Puerto De Santa Maria, Chiclana, and Chipiona for beaches. They will be relatively tourist free, but plenty of Spainards.
Not sure about your timing but there a few festivals to attend during the summer and if you can discount the recent influx of Brits to the scene I believe they are the best all around festivals in the world.
Thereâ??s Festimad outside of Madrid 8-9 June
www.festimad.es Thereâ??s Primavera Sound in Barcelona 31 May- 2 June
www.primaverasound.com Thereâ??s Summercase in both Madrid and Barcelona 13-14 July
www.summercase.com And thereâ??s FIB in Benicassim 19-22 July, which is near Valencia along the east coast. FIB has been my favorite festival, named my boat after the place. But in the last 2 years NME has been a partial sponsor the Brits are insufferable, theyâ??ve brought the brain-dead practice of throwing beer in the air but thankfully not the pissed filled ones youâ??d experience at Reading, V-Fest, or Glastonbury though Iâ??m sure itâ??s not far behind.
www.fiberfib.com As far as flights, Iberia will start a nonstop service from Dulles to Madrid and Barcelona in June, they have specials of $699 booking by May 31st, these prices are good through September and to say the least they are great deal. Also look at British Airways, they have a flight to Heathrow leaving BWI at 8:45 nightly and you connect to most Spanish cities through them. Similarly with American, from National via JFK or Miami.
Anyway if you need info from an American perspective I lived in Spain for 7 years, go there about 3 times a year, and still have an apartment over there, just PM me.