My advice if you are going to stay only 3 or 4 for days is to visit the city of Valencia, it has a lot to see.
Visit the port of Valencia at night, it's great to have a drink and at midnight the play a light show.
port By this time of the year the paddy fields are green, don't miss them. Go to eat rice to El Palmar. From El Palmar drive to Sollana, and then to Sueca and Cullera, to enjoy the rice plantations landscapes.
You can eat at restaurant Racó de l'Olla in El Palmar.
www.racodelolla.com Take a boat at la Gola del Pujol (El Saler) to see the Albufera sunset, don't forget your camera.
Albufera It is also time for the beach. Go to the south, Cullera, Gandia, Denia.
You can eat a delicious paella in restaurant Casa Salvador and after that have a wonderful bath in the beach, 100 mt. from the restaurant. Call for a reservation, ask for a table at the terrace.
http://www.casasalvador.com/ Valencian mountains are not high but if you want to see beautyful landscapes go to Játiva (Xàtiva in valencian language), Mogente (Moixent), Onteniente (Ontinyent), Bocairente (Bocairent) and Alcoy.
Have fun