Welcome to SailNet! Those Marshalls are nice boats. Do you keep your 18 in Duxbury Bay? If so, I may have seen it at some point or another while poking around the Bay in our dinghy
Hopefully you will get a reply to your questions from an owner. No first hand experience here, but I agree with comments above that you could cruise far afield on a Marshall 22. They are certainly large enough for two crew -- probably nearly as much interior volume as a conventional 30 footer. One of their big limitations is tankage -- not much fuel
or water (12 gal and 22 gal, respectively). The necessity to re-fill regularly makes them more suited for coastal hopping.
Also, I would personally be hesitant to do a Gulf Stream crossing with one. Catboats have loads of form stability, but are not self-righting if they go over much past 90-100 degrees. This limitation is yet another reason they are primarily suited for coastal cruising.
MAYBE I'd hop across to the Bahamas from FL in an ideal weather window, properly equipped, after gaining experience in the boat and learning its idiosyncrasies. Once there, it would be great in the shallows! But in the remoter parts of the Bahamas, tankage might become your biggest limitation again.
P.S. Conway's Catboat Summers
(recommended above) is definitely a worthwhile read, but it is simply a compilation of the Buckrammer
articles that were published in Messing About in Boats during the mid-90's -- in case you already read those.