Before I left on my trip I visited a "travel medicicine clinic", told them where I was going, and they set me up with all the right medication. I had malaria pills for central america (chloroquinine). Hepatitis A and B, Tetanus, Typhoid, Flu, ETEC (travellers diarrhea), Yellow Fever. They also gave me a prescription for an antibiotic to carry with me (Ciprofloxacin) to treat a bad diarrhea while on the road.
Your documentation sounds correct. I would visit the AAA and get an international driver´s license. In fact, get two copies. If the police hold you hostage looking for a bribe by taking your license away, you can walk away and still have backup.