I have to 2nd the whole "learn spanish where you want to live", if you want a beach go there, city go there. It all depends.

Saying that I just returned from BsAs after spending 6 months down there. I went there witouth knowing any spanish/castellano. I studied with private tutors in Palermo Soho, also at a language academy called vamospanish. Both are very good for early stage learning.

Once you progress in the language you will want to break the class structure and begin to have real conversations. Couchsurfing is great for this. They have a language exchange forum where you meet up with somebody and exchange your language for theirs. You get to learn the language plus make friends with locals, it is actually how I met my girlfriend who is from BsAs.

Good luck with your travels and I hope BsAs will have what you are looking for. I know it did for me, haha.