Re: $3000/mo cruising budget
We were there in 2010 so things may have changed. To be clear, there are two gets of costs: the Canal and the country.
Canal - You can check online to see the charges. What can really boost these are the extra things you can spend money on, like using an agent, hiring line handlers, lines and fenders. These can easily cost as much as what the canal charges. We did everything DIY and our total costs (including buying a cell phone and time) were about $15 beyond the canal fee.
They do measure your boat and if there is any way to get under 50 feet (counting everything that sticks out) it is well worth the effort. Our 45 footer measured 48.5 because of the anchor roller and Monitor vane (with the blade down for the measure; with it up it would have been more and very close to 50). We had friends with a 44' cat who removed their sprit. Removing davits would be a great idea if you are close.
- Country: It is not one charge, but they hit you for everything and at every opportunity. There are officials for immigration, health, port captains, biosecurity (I know I am missing some). After we did the canal we went to fuel up at the marina in Balboa and three more officials showed up. It was $30 for this and $75 for that. They all went out of their way to say how it could be more but they were being nice to you. I loved the Latin American countries we visited but the officials are a PITA.
Finished the circumnavigation in early February in Grenada. Have to work on a book project for the next several months so the boat will be waiting for next year.