MULTI-HULL!
I don't have any recommendations in specific or particular brands, but with that
budget ($50k) and starting so in advance you should have plenty of time to not only get some good recommendations, but actually some sailing time on the
boats being considered- we can recommend all kinds of things, but really, for long-term use you ought to take any recommendations out and try them out for a day or so!
One thing I'd offer-
have you considered a multi-hull? If I were going to cruise those areas, especially with kids, I'd look into an older Cat -Not only are they normally VERY shalow
draft (perfect for that part of the world) but they're VERY safe (unless you plan to take on some serious hurricanes in the high latitudes, and even then...with
experience... very safe)... but with the hulls
you'd get more privacy for you, and the kids in the other one. That's something I'd think about for long-term and having teens aboard (we might not care as much, but teens really want their own spaces)!
Or maybe consider
an older Trimaran -though they usually lack privacy for separate quarters until you get into the fairly larger ones (unless you go with a Jim Brown
Searunner with the aft cabin-dinette, which with $50 you could really set up nice AND have plenty left over for cruising!)...
Those cruising grounds are PERFECT for multi-hulls. And you'll see TONS of them there- for a reason! Tons of
deck space, privacy in the very separate cabins, and LOTS of room to lounge around, and VERY safe -and with their
shallow draft, you can get ANYWHERE (even up on a beach!).
p.s.
You won't get a TON of difference between multi-hulls so not as strong need to go sailing in them (vs. monohulls), so it's more about layout and interiors -something that fits your needs and has the right accomodations.