Getting from BC to St. Kitts comfortably will call for a decent-sized boat, as does living aboard. Crew size will also have an impact: you don't want something too big to handle with the number of crew you plan to have aboard, or something too small to fit the number of people you want to have with you. It would seem that boats around 40' with adequate storage for long passages would be a good place to start. Passport 40's have a good reputation for this sort of use.https://sailboatdata.com/sailboat/passport-40/ . A Beneteau 40.7 would not be a good choice.