I did a cruise last year and that is a great choice. You get to see a few different islands, food is free, quite a few free entertainment options (I went surfing, boogie boarding, ice skating, rock wall climbing, ice show, plays, headlining show, comedy show, water and dive shows, there was a zip-line that I didn’t do, basketball courts, table tennis, mini golf, arcades, library, gym), there are activities for teen, kids, toddlers. Besides your fare, you only pay for extras like specialty dining, tours and things like that which you don’t really need. I did one tour which wasn’t overly expensive but on the other stops I wandered with some friends, I did not feel unsafe at anytime. If you follow practical safety precautions that you would anywhere, don’t walk alone, don’t flash large amounts of cash, stay in public areas that sort of thing you should be fine. You have a number of cruise lines to choose from and a couple of them offer Mass daily and all have a chapel.