Travel possibilities from Puerto Rico to the rest of Caribbean

Hello! Me and a friend are travelling to San Juan and from there through a majority of the Caribbean islands, and I am curious as of the travel options to get from puerto rico to the other nearby islands. I know there are flights between most islands, but I’m trying to make the trip more affordable if possible (If you know any travel methods further down along in between the caribbean islands, that’d be great to hear about too)

I am mainly looking for alternatives to taking a plane in between these locations, so that would be preferable.
Mainly:
– St. Kitts & Nevis

– Saint Martin

– Antigua and Barbuda

– Guadelope

​

I’m also going to depart from San Juan back to my home country at the end of the trip, so if you know any travel options from Aruba, Curaçao or Trinidad and Tobago – back to Puerto Rico, i’d be very happy to hear some suggestions there as well. Thanks!