Cannot help really with PR as we have only done over nites or just a few days, but the Condado area would be a good option for PR.

Domican is primarly all inclusive, not bad, just that is what they would be looking at.

Aruba and St. Maarten would be options. Some all inclusive in St. Maarten but not much. Aruba has more all inclusive but also a lot of hotel/time share options. Both would be easy to get around and confortable for someone that has never been out of the US before.

Cancun would be another option.

Thinking that they might prefer to be somewhere where English is generally spoken by all, easy access to beaches and watersports. Food options and cost with non all inclusive is easy and does not have to be expensive at all in the islands listed above. Fairly easy to get around in all of the above with the exception of DR really, but there it would be an all inclusive resort and would only be leaving for organized tours more than likely.

Caymans would be on the upper end of any budget. Jamaica would be all inclusive also.