Busca las películas Juana la Loca (Mad Love), La Lengua de las Mariposas, Belle Epoque, Todo Sobre Me Madre, Abre Las Ojos . . . . . No soy seguro que todos son castillano, pero todos son de España. También prefiero el castellano.

There's a huge difference between modern Spanish as spoken in Madrid, and the Spanish of, say, Mexico.

If there are colleges or universities nearby that have Spanish courses you might check out what textbooks they are using. I still have my Spanish textbooks from university Spanish courses (I was able to buy them used as well at the university book store).

An excellent textbook:

"Spanish Grammar" by Conrad J. Schmidt with new online audio recording. Schaum's Outlines.McGraw Hill Education.

"Use with these courses: Elementary Spanish 1, Elementary Spanish II, AP Spanish, Intermediate Spanish I, Intermediate Spanish II."

Àn old company, with a proven track record.

[linguaphone.co.uk]