Cruising can be great fun, but you should tread cautiously, Honest Frankie. I've worked on three summer cruises (although not as a musician). Crew/staff accommodations are far from luxurious. Hours for the band and for the musical acts can be long – bands and musical acts can be assigned to play background music for lunches and dinners as well as after-dinner shows, which can run quite late; and entertainment staff (including musicians) can be assigned to accompany daytime tours, etc., which isn't necessarily a bad thing if you're visiting places you want to see, but it cuts further into your free time. Pay usually isn't great since you are receiving room and board while you're sailing and the employer factors that into your take-home. But, it can be lots of fun at least for the first few times, and you can get to places you couldn't otherwise afford to visit. Go for it! Just ask lots of questions of your prospective employer(s).