These people will help you with permits, insurance, entry papers, understanding local regulations, reservations, and other formalities of sailing to and in Mexico.
Written for British boaters going to other European countries, but useful for others as well. Covers papers, competence certificates, insurance, and other requirements.
To give you some idea of what you might expect, here's a ranking of countries by their perceived level of corruption. Not specific to the type of corruption that sailors meet, of course, but useful for pinpointing where your itinerary may need more research.
If you are planning to take your boat into Europe, this firm will help you obtain the required CE marking that makes the boat legal to sail or sell in European waters.
A fill-in -the-blanks form for listing crewmembers and describing your boat, to use when entering a foreign port.