I have been to both Hawaii and Cancun. It is true that Cancun is all tourists the only Mexicans are the people that work there, but the beaches are beautiful! Hawaii is also beautiful the beach is a bit rougher though. Very fascinating. You do also feel safer. This may sound biased since I just got back but have you considered Puerto Rico. It is beautiful, there are lots of things to do and see. It is very historic and the beach is wonderful. There is El yunque which is a rain forest you can go hiking in. All together its a great place. Wherever you go you will have a wonderful time. Between Hawaii and Cancun I would go to Cancun but make sure to rent a car and drive to the capital and visit the ruins.
Hope you have fun
