Me and my family would like to take a cruise to the Caribbean for at least 5 days. There will be 2 adults in their mid 30's and 2 16-year-old daughters. I was mainly looking for the best cruise for the teens though.. maybe with a spa and pool... and other fun features..I also want to find the least expensive cruise, but the more fun cruise for them. What would be the best ship to take them on?and why?