Stop at the Police dock
on Shelter Island and they will issue you a 30 day anchoring permit
and show you where the usable anchorages
are. (You can renew this permit
twice for a total of 90 days.)
For liability insurance I get mine on line (the site is actually called MexicoInsuranceOnLine or something similar). They are brokers for the same Mexican insurance companies everyone else has, but you can print your declarations page right off the Internet
, no waiting.
You can also get a Mexican fishing license
on line (CONAPESCA).