You can take the word marina out altogether.
I only ever go in to the fuel dock. Ok it's different while I am cruising the USA but I have saved for that.
As far as I see the biggest expense in you early move would be the Panama Canal.
With that and boat prices in Florida and the Caribbean I think looking there is a good idea.
As Arron said many things he has tossed off his boat. Don't chuck the engine, but don't buy anything whatsoever in the first year. Except solar panels.
I always worry when people use the words refit or outfit. WHAT? What does one need to outfit? All reasonable boats that you can buy for $70k should have sails, GPS, plotter, refrigeration and a good autopilot. What else do you NEED?
Ditch the idea of a water maker and buy a blue Jerry jug for $20
You are in the tropics, do you NEEEEEEED a new Bimini, enclosure, added canvas? Buy a boat with that crap on. I have a Bimini and after 4 years would like a dodger, but that's after 4 years.
An epirb cost $400, cm93 charts downloadable off the net and Opencpn is free. You don't need radar as there's no fog in the tropics. You're not crossing the Atlantic so why spend $3k on a life raft.
You do need a dinghy and outboard, but start small and old. Second hand outboards in Florida are $500 for a 9.9hp.
Don't listen to all the crap about storm sails, rerigging, keel bolts, generators, wind vane steering, wind generators.
One other thing, you seem to be stuck on one boat brand, and an old series of boats. Remember salt water, no matter what old sailors say, ruins boats. Anything from the 1980's will be very old. Expand your horizons.
Just as an example, I'm not suggesting this boat or type, it's just that I know them, and their prices cos I own one... http://www.yachtworld.com/core/listi..._id=40064&url=
2002 year, 39 foot, asking $89,000 is probably ex charter and done up afterwards. I would think $70,000 could get it if the guy is motivated.
At least it's a start to looking at other boats. IMHO far better than an 1980's boat for $50,000.
All the best.