In the City of Valencia there is Castellano. alot of signage and stuff is in valencian. English is very hard to come by unless your at tourist places. there is alot to do here. alot of nightlife and places to visit.

My spanish is very poor but I understand alot and I get by with French and very broken Spanish. People here are very understanding and want to help. Valenciano is a bit of French mixed in too.

I live in a smaller town that is only 8 minutes by train into Valencia. It is alot cheaper then the city. I guess it depends on what u like. by bus, metro or taxi you can get to everywhere.

what kind of experiences are u wanting?

Our area has a accent that people say is very strong, but you get used to it, and if you can understand the older generation then you can understand anyone, mainly the older people are broad, the youngers seem to be a lot better, the thing is, is not to copy the accent, stick with finishing our words, the s is dropped a lot, but its not difficult to add it yourself. Tv and internet are good tools and they have all accents to learn from.

Also if you mix with the educated people you will not even notice it, in the villagers it is more prominent, but no reason not to move to Andalusia, and I could probably count the amount of people I know one one hand that really want to speak spanish anyway

That very much depends on where you go. I met plenty spaniards when I was here and there http://www.fcbarcelona.cat/web/castellano/index.html

OP did not say his objective was to meet with spanish speakers. I think his primary objective was to locate somewhere with good opportunities for R&R. One to one pillow talk is a great way to learn any language <LOL>

The OP said to learn the language and do an "internship". If this is the main priority then I would choose salamanca. If the main priority is to bum around the beach with picking up the language as a bonus then valencia or málaga would do.

salamanca is the equivalent of Oxford and would look good on a CV. British Universities do student exchanges at sevilla and valencia but this includes work experience and the students already have a good grasp of spanish.

We have a holiday home between Valencia and Alicante, and our daughter did the 'year abroad' section of her degree (Hispanic Studies with English from Kings College London) at the Universidad de Sevilla. Sevilla is a magical city, lots of language schools, and plenty of opportunities to take a bus to the beach (at Cadiz I believe) at weekends. She would return to Sevilla in an instant

Might be true, but what a sad reflection on the people that have chosen to to live in Spain . It's the old story, we decry immigrants to UK for not speaking English, for living apart with just their own culture, then people move abroad and do exactly the same. Thankfully most that I know with an interest in Spain are all very interested in learning the language. It's nice to visit my friends and ex neighbours in Spain, the whole family speak excellent Spanish.

To be pedantic OP said
Salamanca may be nice but it is a long way from the beach.

Oh yes they (some of them- indeed lots of them) do!