What are the most important considerations for a boat buyer?
Well...I think a moderate draft and mast height are essenntial for your plans. With kids, one thing you may want is living space and your own privacy and I would suggest center cockpit boats would be worth considering. There''s always been a debate over keel/rudder configurations and a lot of cruisers opt for longer keels with well protected and supported rudders/skegs...but a lot of folks successfully cruise the Carib with standard fins and unsupported rudders found on many production boats so I personally don''t think that is a big deal.
Once you have the basic choice in boats sorted out, you need to think about HOW you want to live aboard. Will you be plugging into a dock? Living at anchor? What kind of refrigeration needs will you have with a family of 4? How much water will you use daily? Will there be lots of electronics needs? What kind of dinghy and engine will hold you all annd your stuff? In other words...will you need a watermaker, generator, lots of battery capacity,davits, inverter, solar/wind charging?
And where will it all go...especially with all the spares you need to carry once you leave the USA? Once you have a sense of these needs, you can then evaluate the boats you look at in terms of what they have and what they will need and what will have to be compromised.
I would buy a used boat that was well cared for over a new and take advantage of someone else having gotten the kinks out but have the engine well checked out as you will be relying on it heavily.
Finally, I''d encourage you to focus on the "living aboard" rather than sailing qualities of the boat. I''ve seen quite a few guys with the boats THEY wanted...with unhappy wives and families because they were cramped and uncomfortable and were not prepared for "camping out" for a year or two!If you are like most...you''ll be sailing 10 or 20% of the time and living at anchor the other 80% and having everyone happy on the hook is more important than sailing 10 degrees closer to windward! All best...