The one place I would love to live is Valencia, granted I'm sure much has changed since I was there in the early 90's. My friend had a flat off Calle
De La Paz and another near the park with the Walt Disney statues. There isn't much room for
gardening in the
city, however going to Piccasent area there is/was a lot of open
land and some of the olive and orange orchards had abandoned housing. It makes me think that they wouldn't mind partitioning some of that land to someone that would follow
permaculture as it would only be a benefit to the area.
Also, there were many farms out West (I believe it was, sorry so long ago) around the sunflower fields. I saw many acres, some with old houses that were unused, again I have no idea what has happened to this land since. Arizona, most likely between Phoenix and Prescott is the one place I've been that has a climate similar to Valencia. Yet, you have the moisture from the Mediterranean to take into account, so the rainfall there (Arizona) will be too small. Southern California and most likely not more north than Bakersfield, CA would be my best guess then for the climate most similar.
Good luck to you wherever you choose.