Hello Corrado,
I wish you much luck on your trip in Brazil!
I myself had been cycling twice in Brazil: 2001 and 2008, in the states of Rio de Janeiro and Minas Gerais. I cycled the Estrada Real in 2008, I've noticed you will do it next year. Very good idea! I liked it very much!
I hope you will not have too much (dangerous) traffic on your coast trip. The Brazilian drivers are not used to cyclists.
Do you will use a GPS system? Which maps will you use?
Maybe I can give you some hints about maps if you need.
Have fun
Helmut