Catalina 30s are just about the most popular cruising
boats ever made. That makes it easy to comparison shop and you should be able to find a good condition example in your
price range. They are also roomy for their length.
The conventional
route from Miami would be through the Straits/Keys/Dry Tortugas and then a multi-day sail to Isla Mujeres in the
Yucatan Channel. If you are a Colombian national, stopping in
Cuba may be an option. From Isla Mujeres you leisurely coastal sail/island hop south to
Panama and then jump east to the Colombian islands and
Cartagena. I've never sailed the western
Caribbean, but I assume there are good
cruising guides like the ones for the
eastern Caribbean.