If you are using The Moorings they have all the info you need. We were on a M4500 Cat and didn't need to get water for 2 weeks (2 people on board). Bring as much frozen meats that you can carry because you won't be able to eat out, no resturants avaiable outside of Placencia. The only problem we had was at customs when we declared the food. We had to pay $19.00US; don ask why. The policy from their government is that you can bring in the food; we kept it in the original packaging from the US. I went to the items to declare line because it was shorter; if you stay on the line for regular custom and not declare the food it is OK. The agents just wanted some extra cash.
They also will tell you where you can go and you probably won't see another boat for days.
s/y NIRVANA, SO49