Not having the opportunity to practice the foreign language one knows reasonably well
is a major frustration.
The best experience I had was taking semi- private classes ( two students) with a very good teacher.
Unfortunately, it was costly .

And you will find the Spanish spoken in Spain different from that in Mexico, luckily somewhat slower.

I too do evening classes, in my case in italian conversation. Our teacher is the same one who teaches up to A level to the day-time students and is a fully qualified teacher, as well as being italian. We have a class of about 8, all about the same level, so we are able to learn from each other as well as her.

all my teacher have been from Mexico, Central or South America...
the difference
has never been a problem
.
Spanish use vosotros ( for " you " plural,) while Mexicans use ..Ustedes
some expressions, slang and pronunciation may vary...but it varies greatly
between Chileans and Cubans as well.

Perhaps you can find a Spain-based tutor who offers online courses (Skype or other software based lessons) in one of the towns you are going to and arrange to take several courses on line and then meet your tutor for an in-person lesson?

I know I have found similar resources while pursuing Italian studies. I attended a school in Lucca, Italy; I believe some of their teachers are involved with an online learning program.

We were having trouble communicating with a taxi driver in Granada, I couldn't recall the correct vocabulary words so I described the words in simple Spanish and it worked perfectly. Everyone will try to help you if you are attempting to communicate in their language.

If you had more time before your trip - March ? -I'd say get yourself a Spanish-speaking boyfriend in order to practice your conversation skills. Do it anyway; a month is better than nothing. BTW, I am a language teacher.

The Spanish and Italians are most generous and accommodating when a foreigner attempts to speak their language. Unlike certain certain countries that will remain nameless like France.

It would be easy enough to find a Spanish-speaking boyfriend before March if it weren't for the little problem of being married! ;)

As I said, find yourself a Spanish-speaking boyfriend !!!