I am planning a similar trip. I just posted a new topic and you might check into that one, too in case I get responses that are useful to you.
I have bee trying to reasearch the same. So far I have come up with:
This is the best website yet. They have been all over this continent:
http://www.geocities.com/kingachopin/
I was so impressed that I spent my meager earnings on a book they wrote. Check it out.
Also,
Ironically, though most of the advice is paranoid and uptight, the State Department website for the USA has a limited amount of info regarding different countries.
Other than that, I have started joining what look like the best traveller forums and posting like you did. Hopefully between the two of us, we can get some good info before we leave.
Good luck,
Drop me an email if you want,
-M