The last of these has just come up from the third division, they were founded in 1935 and are 19km from Bilbao in the Basque region. They play in the Municipal grounds in Urritxe, which seats 3000 spectators and has grass on the ground. This is possibly the Cinderella of the teams but it means they have nothing to lose and everything to play for.
C.F. Badalona was founded in 1903 and is the team for the town whose name it holds. Badalona is 10Km outside Barcelona so by far the easiest to reach from here. It's stadium seats 10.000 spectators but it is astroturf.
The last possibility is Real Jaen who were founded 1922, The Andaluz team have played three seasons in La Liga and were last in 2A in the 2000/01 season. Their games are played in the the Nuevo Estadio De La Victoria which is grass and holds 12.569 spectators.