jeromesteele hi!
I am actually a bit envious as you are going to spend time improving in two of the most fun and beautiful styles - awesome!
For me the way into these styles was, after a lot of listening and your basic practicing, through playing with experts. I got some gigs in a batucada with Brazilian musicians. That way I got to learn the percussion parts. Then a Brazilian drummer needed someone to sub for him on a few gigs, so he actually taught me the rhythms (his band played Afoche, Foho, Samba-Reggae, originals, covers of Djavan, Olodum - it was great) and made sure I could replace him on those shows. I went to as many gigs as I could of that style, and since Brazilian music has a lot of loops in the drum parts, one night I transcribed the whole gig played by my mentor. It was a great learning tool!
For Cuban music, I found the co ordination to be more of a challenge, but El Negro and his book "Conversations in Clave" came to the rescue.
Some things you could do are:
1) Immerse yourself in the music you want to play. Learn the songs, melodies and all. Not too many tunes to start out with, but learn them well. Figure out what the drummer is playing, transcribe or memorize and learn the parts.
(I read an interview with the great Omar Hakim in which he said dancing to the beat you want to learn is a great way to get it.)
2) Break down difficult bits into exercises. Loop the challenging parts at a slower tempo.
3) Listen to the groups playing those styles with no drummers, just percussionists. (Afrocuba de Mantanzas for example, and for Brazilian check out some batucada's).
4) If you can play for some groups where everyone is good at those styles, it will be very helpful. If there are Brazilian batucada groups you can join and just play surdo or caxia, it will really help and give you a great vocabulary for drumset.
5) For Cuban, check out Conversations in Clave by the great Horacio "El Negro" Hernandez. To me that is one of the best tools out there for gaining freedom within this style. He takes no shortcuts, so going through it is a slow process, but pays off! (I spent a long time learning a few tunes he played on someone's CD, but then found out I didn't have the ability to actually play freely in the style. Luckily he brought out the book, and 6 months of practicing with it really helped!)
(reading this I realize 1 & 2 are probably old news to you and everyone else, apologies if I'm repeating what you already know.)
Hope this helps. Once you have some results, let us hear them!
Ami